A person who is involved with twat in a petty and/or contemptible way.
See also fishorcheesemonger.
Example 1
Person 1: Hey where's Billy?
Person 2: I don't know -- that twatmonger is probably elbow deep in cunt right now.
Example 2
Person 1: So I'm not sure why the girl I'm trying to date is upset with me.
Person 2: Maybe because you're trying to date her but you flirt with her friend who likes you in front of her face.
Person 1: No dude it's cool though because I don't like her friend like that. I just like flirting with her.
Person 2: *Sigh*. Piss off, twatmonger.
Trans people who are constantly pushing the "trans rights" agenda into people the second they spot the smallest reference to "genderfreedom. These people are the toxic side of the trans community (as opposing to the more wholesome, loving and supportive side), and are usually aggressive to the point of canceling any of their "enemies" into suicide.
"Jack: Dude... Someone was talking about Data from Star Trek supporting trans rights, just because they let them choose a "gender identity".
Allan: Man... These transmongers are so obnoxious sometimes."