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DEF means that something is really good or to someones standards.

DEF also means not being able to hear anything

DEF does NOT mean definitly
That concert last night was so DEF

Yo Im DEF from that concert last night
by yosoypopichulodelanoche June 11, 2009
11 34
The hip/gangsta way of saying Death.
According to the Ali G Show,
Ali: "Yo, lets talk about this thing called def man. You know, D-e-f"
Doctor: *my God this man is a complete moron*
by Well Thats my Mama May 10, 2005
12 35
short for definetly...
"that is most def the best damn thing i ever saw"
by Allison September 24, 2004
9 32
short for "definitely"
Ah you're def close to me then. If you're tech savvy, I might just need your help to give me a hand in hooking up my comp at my soon-to-be home.
by wiCkEd eEv January 27, 2003
30 53
Short for 'defective', which means 'the Ultimate', superlative, better than good...

This started some time after Michael Jackson's "I'm Bad" video, in which 'bad', of course, meant 'good'.

So, to denote a meaning that means the ultimate superlative of 'good', people started using 'defective', which of course is the ultimate superlative of 'bad', and which then was simply abbreviated to 'def'.

Russell Simmons' Def Comedy Jam
by reality_bytes August 16, 2007
5 31
abreviation for the word definately, usually used by kids who are either way cool, or way lame.

the only way to pull of using the term "def" is to be the first one around to use it. if you're just copying someone, people might think you're lame.
Kara asked if the new guy was cute.
Emily repiled, "Oh most def! He's soo hot!"
by Kara April 25, 2005
30 56
short for "definatley"
"That is def the ugliest thing I've ever seen."
by Laurie *is hot* April 09, 2005
4 32