Someone who is/does/says something infinitely stupid and dumb; someone whose idiocy is unmatched and unrivaled, and is beyond words. Someone who says something so stupid that you're left gaping and speechless, and the only word registering in your head is Chutimo.
"I wanna be called Chutimo all my life!!"
"Hey Chutimo, do you have a lecture now?"
"OMG you're such a chutimo!"