
Tr*p
It's a slur used against trans women. It was originally used to imply that trans women were just men tricking people into sex. It's normalised in the anime community, but it can be triggering for some people. I used to use the word before I found out, so recently I've stopped saying it as I myself have some very close trans friends that find discomfort with the word.
Sorry if I come off as an SJW, that's not my intent by the way. I just wanted to explain. I have no power to stop people from using it, so all I can really inform people about is that it originated as a slur.

Sorry but that is false.
A trap is a male that crossdresses to lure in men, often enjoying their reaction when the men discover the secret. This is a term that originates from anime/manga and has nothing to do with trans women or trans men.
I know that the SJWs try to make this a slur as of late with the meaning you stated, but that is not the truth, mind you.
Oh god that slur at the end jumpscared me