1. One who thinks themself to be teh best.
2. Loser, Poopie, douche nozzle, etc. although very cute.
I'm the best, I'm so MacMill.
a sex god in which all girls wish to wrap their ovaries over his cock. usually macmills have very seducing balls which can make a girl have multiple orgasms
he was a real macmill last night he fucked me soo hard i could see jesus