Someone who 'tries' too 'hard' to present themself as their idea of "cool", oblivious to the fact nobody else feels that way about their expression, instead coming off as corny / cringe-worthy. This might be a dude doing a burnout while driving past a group of unimpressed girls, or a pampered middle class youth displaying the gestures and sentiments of a hustler.
Person 1: "Did you see Kevins instagram post fronting like 'mr money' with like $80 in his hands?"
Person 2: "Yea I tried not to say anything... that's barely 1 days work... he's such a try-hard"
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Person 1: "checkout that try-hard with the frosted tips and Guy Fieri shirt.. oh wait that's actually Guy Fieri"
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Person 1: "Rob deliberately turns his music up like a full try-hard when driving past people dude, he thinks he's so cool"