Meaning of ガチのM

Question

Context: some schoolgirls are talking about a girl that is dating a boy that killed someone when he was younger.

ついてく男のせいでバカ見てるよね。自分から人生詰みに行ってるよね。ガチのM?　夜はあの人殺しから攻められるプレイしてるとか

The only meaning of ガチ I could find was "serious, diligent", but I don't think it fits the context. Judging from what the girl says (攻められるプレイ) and from results in Google for ガチのM, I guess the M stands for masochism. Is this correct? If yes, could you explain the meaning of ガチ and how it can be used to form words? Thank you for your help!

Answer 1

Yes this M stands for masochist. This initialism is very common in Japanese, and people don't usually bother to say マゾ or マゾヒスト in conversations. In this context M primarily means the girl is a type of person who willingly take troubles and put herself in a hard situation. Of course the last sentence has a sexual meaning.

ガチ is genuine, true, or real rather than diligent. ガチ is from a sumo-term ガチンコ, which is an antonym for 八百長. So "not a fake/mock" is the original meaning of ガチ.