IMO, there is no "evil" where there aren't any actual intentionally helpless casualties.

A fantasy one does not enjoy? Is such a thing possible? :chin:

I don't suppose the word fantasy as the best fit. A fear of loss of control and enjoying the experience, perhaps, but it would be more of a fear or concern as opposed to a "fantasy" if they do not explicitly enjoy the thoughts of doing so. No?

Evil is a tricky concept in philosophy, some say it simply doesn't exist as a strict absolute. But short of that crowd I would say it's far from bold to suggest the actions you're describing, as well as the thoughts thereof would be considered such by most all people.

Let's use the term severely socially undesirable. That has absolute definition if not in relativism and covers everything from rape and murder to tailgating and abusing grocery store free samples.

Are they inherently such? There's definitely something atypical about them, that's for sure. Maybe their heads just screwy, for lack of better wordage. Similar to schizophrenics or those who suffer from severe tic syndrome such as Tourette Syndrome. Some basically can't help insulting people and even picking up weapons and gesturing with them as to harm someone. I'm no doctor but it's almost like a normal brain has a compartment for everything that is "wrong" or "socially unacceptable" and most people are able to accurately store, identify, and avoid such behaviors or actions whereas those with the ailment are the opposite, as if the "compartment" is forced open or the border between such is non-existent or dynamically shifting by no control or effort of their own. If that's accurate they're not purposely that way, per se, right?

I had this same question years ago: "Is having bad thoughts immoral?". I think that for every ethical theory out there, the answer is no, especially when many thoughts are involuntary. Except for ethical theories that define moral as that which attends to a certain desirable goal or principle in general, and so having bad thoughts is immoral because they are harmful in a way; but then they remove will from the picture — which I dislike —, making it such that inanimate things can be deemed moral or not.

William Blake said "He who desires, but acts not, breeds pestilence."

If someone had constant thoughts and fantasies about raping, torturing, killing etc people that they may or may not enjoy but were perfectly moral in the real world (either for its own sake or from fear of consequences of acting on said fantasies) is it reasonable to describe such thoughts as evil?

What about describing the person as evil in nature even if they never act on them?

Is this a sound moral judgement or just thought crime? — Captain Homicide

I find that the OP muddles the issue by not differentiating between different types of thoughts a consciousness can be aware of.

Regardless of where one stands on the issue of causal determinism, thoughts tout court can and should be minimally classified into two varieties: a) those of one’s own mind that appear to one as a consciousness involuntarily and b) those that one as a consciousness voluntarily enforces within their own mind if not also at least in part creates. Memories, for one example, take on this dichotomy: some are involuntarily remembered (as one extreme, such as can occur in post-traumatic stress disorder where the consciousness remembers things even though not wanting to so remember), and some are voluntarily searched for and thereby brought up to consciousness, i.e. are voluntarily re-called.

Involuntary thoughts can in turn then generally be voluntarily reinforced or else voluntarily shunned. One has a negative involuntary thought X; does one succumb to it and thereby consciously endorse it or else deem it bad/wrong and thereby distance oneself from it?

To deem this very choice-making (be it one of free will or not)—choices regarding which thoughts are right/good and thereby to be upheld and which are wrong/bad and thereby to be discarded—irrelevant to issues of morality is to maybe all too inadvertently remove all a psyche’s conscious intentions as to what ought to be from all accounts of ethics. And—for one example—without intentions mattering ethically, there could then be no ethical difference between justifiable homicide, manslaughter, and outright murder.

Otherwise, the thoughts one voluntarily chooses to think and thereby endorses are a staple aspect of what one is morally responsible for. Especially when considering that thoughts regarding what one ought to do predispose one for so voluntarily doing. So that the person with recurrent involuntary bad thoughts that voluntarily rebels against all such will be virtuous in character, whereas the person which voluntarily reinforces the involuntary thought of, for example, “I ought to kill all people of type A because they look funny” will not be (even if their circumstances never result in their so murdering).

Other examples could be given, but I so far think they all can be addressed in manners just expressed. In short, the thoughts we endorse are voluntarily, intentionally, upheld by us. And our intentions matter ethically in what we are, do, and become.

If not evil then what term should we use? Deviant? — Captain Homicide

Though I can understand the usage of "evil" in certain contexts, I’m not big on the term. How about “harmful”—and thereby wrong and unethical.

Of course you can have evil thoughts. Everyone does and we all - non psychopaths - know they are evil when we have them. Having them doesn't make a person evil; it simply reminds him that we all have in us the capacity for evil. That's why we invented the term. Externalizing it as an imaginary person or force doesn't change the fact.
But we usually don't act on them; the moral person resists that temptation.
Fantasy, especially deliberate indulgence in fantasizing, is a step toward evil. The next step is wishing, and after that, intention, followed by planning and execution. The healthy response to evil fantasies is not to suppress them, but to analyze and thereby disarm them.

:100:

The healthy response to evil fantasies is not to suppress them, but to analyze and thereby disarm them. — Vera Mont

I don't think so. I think that to believe thoughts can be described as evil is the result of a superstition of language.

I say this because thinking is one of the least consequential and impactful activities human can engage in. If they were to store the kinetic energy produced by any of amount brain activity and release it on the world I wager it wouldn't move a feather, let alone produce any evil. Even when thoughts are reified into a phrase or book, one could observe the words for 10 lifetimes and see nothing come of it. They are completely innocent.

If someone had constant thoughts and fantasies about raping, torturing, killing etc people that they may or may not enjoy but were perfectly moral in the real world (either for its own sake or from fear of consequences of acting on said fantasies) is it reasonable to describe such thoughts as evil? — Captain Homicide

Classically one becomes culpable for an evil thought to the extent that one wills it. So a thought of rape that is in no way willed or assented to is not an evil act, but to assent or intend such thoughts is an evil act. Even on materialism, although the evil act does not harm another, it does harm oneself and inclines oneself towards acts of rape.

I say this because thinking is one of the least consequential and impactful activities human can engage in. — NOS4A2

We have three kinds of action: automatic (motions of body that do not require us to be conscious or aware) instinctive (emotional response to stimuli, over which we don't always have control, or have imperfect control) and deliberate ones that proceed from conscious thought. Most evil thoughts are not translated into action, but no evil act is performed without forethought.

If they were to store the kinetic energy produced by any of amount brain activity and release it on the world I wager it wouldn't move a feather, let alone produce any evil. — NOS4A2

Once it's trapped in a battery, no evil produced. While operating human bodies, all the evil in the world.

Even when thoughts are reified into a phrase or book, one could observe the words for 10 lifetimes and see nothing come of it. — NOS4A2

Or precipitate a world war in one lifetime. Or nuke 180,000 people in an hour.

They are completely innocent. — NOS4A2

Words are not even innocent when read by impressionable youth; they're guilty as sin when written as commands and read by obedient drones.

We have three kinds of action: automatic (motions of body that do not require us to be conscious or aware) instinctive (emotional response to stimuli, over which we don't always have control, or have imperfect control) and deliberate ones that proceed from conscious thought. Most evil thoughts are not translated into action, but no evil act is performed without forethought.

If an evil person is someone who acts immorally and wickedly, they need to act immorally and wickedly, and thinking just doesn’t rise to that level as an activity or behavior. If you were to observe someone having evil thoughts versus someone having good thoughts, it would be impossible to determine which one was evil and which one good unless the performed some other act.

Or precipitate a world war in one lifetime. Or nuke 180,000 people in an hour.

What combination of words and letters could force you to push the button?

Words are not even innocent when read by impressionable youth; they're guilty as sin when written as commands and read by obedient drones.

Words are wholly innocent. The blame lies solely on those who act on them.

If an evil person is someone who acts immorally and wickedly, they need to act immorally and wickedly, and thinking just doesn’t rise to that level as an activity or behavior. — NOS4A2

Thought is the necessary precursor of deliberate activity and behaviour. The thoughts are evil before the person decides to do evil and thereby becomes evil.
As for their "need to", I very much doubt it. I think, rather, they want something, which can be acquired or achieved by mean of evil deeds.

If you were to observe someone having evil thoughts versus someone having good thoughts, it would be impossible to determine which — NOS4A2

Correct. Before action is taken, only the thinker knows. If those intentions were visible, most crimes could not take place.

What combination of words and letters could force you to push the button? — NOS4A2

The ones that spell out your oath to serve. (And the subtext of punishments for refusing a direct order.) Some people have strong enough convictions to refuse anyway, and some are incapable of carrying out certain actions, regardless of the consequences. But since there is evil in every human mind, the words only need to release the repressed evil waiting for expression in those who are willing to act.

Words are wholly innocent — NOS4A2

Individual words are innocent. Some combinations express thoughts, ideas and desires that are evil. Words are mere symbols; have no character or moral value. They can be, and are used to convey all kinds of messages.

The blame lies solely on those who act on them. — NOS4A2

The blame is shared by all participants in a conspiracy to commit evil.