(n) A rant or monologue that begins with the word or exclamation 'Man.'
(v) To go on a mant.
Person 1: "Man, I hate it when you're eating a creamsicle and you're trying to eat all the popsicle bits first so that you can enjoy the cream just by itself, but the cream ends up thawing in the process and sliding down the stick, thus getting all over your fingers."
Person 2: "Woah, chill. No need to mant about it."