English equivalent of ‘sakaurami’?

Is there a word for 逆恨み in English? The translation I have is

1. being resented (by someone one holds resentment towards)
2. thinking ill of a person based on a misunderstanding; unjustified resentment caused by a misunderstanding; responding to kindness with resentment

Which sounds like grudge but can be unjustified in nature. Can this be used interchangeably with 復讐、恨み or 憎む? I'm wondering if I am translating this word correctly.

Context: a group of people are being hunted and killed by a group of killers. They suspect that the company they worked for might have done something to offend the killers, which resulted in this 逆恨み.

"じゃあ、これ逆恨みことじゃん!!"
I translated this as "Then, this is retaliation!?". Not a correct translation, but it just sounds slightly better than using the word "grudge". I thought of using "revenge" or "vengeance", but neither are correct, either.

Thanks in advance for any explanation! :D

復讐 is revenge, 報復 is retaliation, 恨み is grudge/resentment, but one important meaning in the word逆恨み is definitely that “unjustified” element – they hate you for something good you’ve done for them but either it eventually lead to bad consequence, or they just twisted the whole thing and hate you anyways.

So if you get attacked though you’ve been good to them, it’s that “unjustified resentment/hatred.”

But for this line (in a novel or comics I guess), if the one being hunted exclaims in despairじゃあ、これ逆恨みってことじゃん！, I might translate it as something like: “We don’t deserve this, right?” “We didn’t do anything to deserve this!” or “They are hunting us for no reason!”

If "retaliation" doesn't work, I would write, "They're trying to kill us just because of THAT!?" after making sure readers know from context what "that" represents. Or something like "Is THAT why!?" or "That's not fair!" might work, if you create the context right.

When translating, you need to translate per context instead of word by word. Often the context can mean a whole book.

Well, I chose the word "retaliation" because I thought it makes more sense in the context of the story. Or revenge would have been fine as well. But from the story, until the current point, the company of this group of people has been suspected of doing not-so-good things, but cleared of guilt by court.

[So if you get attacked though you’ve been good to them, it’s that “unjustified resentment/hatred.”]

That part doesn't really make sense, which is why I'm confused why the author decided to use this word 逆恨み. Perhaps he only meant to use it as "being resented", and without the underlying unjustified part?

I don’t know the story, so I cannot comment on what they did/didn’t do, but this word “saka-urami” versus “urami” (simple “resentment” or “grudge”) definitely expresses that at least the one who’s saying it considers it unjustified.

The word “saka-“ comes from the word “sakasa,” meaning “reverse” or “opposite,” and put into the word “saka-urami,” it has that sense of twisted revenge/retaliation, not justified.

Maybe putting in a phrase like "so THEY think they're retaliating? For what?" kind of comments might convey the feeling that the one who's saying it feels they are being wronged/retaliated wrongly.

Perhaps "gyaku-gire　逆ギレ" is a word more familiar to people today. It's the same thing as "saka-urami" only that it's a slang.

The idea is this:

Person (or group) A unintentionally offends person B. Then B intentionally offends person A in revenge. This means that B is doing/feeling "saka-urami" towards A.

But intentions and the degree or form of revenge may differ depending on the culture. Maybe that's why you don't think it makes sense.

For example, if B is trying to kill A when he should be filing a law suit instead, this is "saka-urami". If A unintentionally offended B, and B didn't like it, B can express it in an adult manner. But overexpressing it may be viewed as "saka-urami".

Another example: A's job is to sell A's merchandise and B's job is to sell B's merchandise. A sold better than B. Then, B should be an adult and do his best to sell B's merchandise. Instead, if B tries to prevent A from selling more of A's merchandise, A could see this as "saka-urami".