I.S.M. is short for Italian Supermodel. It often refers to a gay guy that is very photogenic and dresses really nice.
"Dude, did you just see that I.S.M.? He was wearing a fucking scarf!"
"I swear, I.S.M. is being such a camera whore!"
"I swear, I.S.M. is being such a camera whore!"
by Tight-ass January 02, 2009