look up any word, like cunt:
 
1.
A "def head" is a wannabe musician and/or songwriter who thinks they are far more superior musically and technically to other musicians and songwriters when actually, for a fact, they absolutely suck.

Most def heads tend to be 13-18 years old, and have very little (one or two years) expirence playing their instrument (guitar, bass, drums, ect.). Most def heads are self-taught players and belive they do not need any form of proper lessons or music theory because they are musical geniuses right out of their mother's vagina. Some def heads are aware that they suck but dont have the balls to admit it. Def heads usually form really shitty bands with other def heads. A def head doesnt play music with any passion or feeling and only plays for money, fame, and sex.
EXAMPLE:

Franklin The Noob Guitarist: "Man I'm such a beast at guitar! Nobody can touch me!" (plays really shitty genric punk riff)

Yngwie Malmsteen: "You're a fucking def head! That sounded like shit! Step aside and let papa show you how its done!" (plays mind blowing solo)
by MAVEDUSTAINE October 19, 2009
 
2.
A fan of DEFTONES...A mostly honorable nickname actually!
Evan: What is the best band; Incubus or Deftones huhh?

Jones: How dare you mention the mighty Def´ in the same sentence as that lamecore popfunk band of wankster?

Evan: You are such a Defhead...

Jones: Hellll Yeahhhhhhhhhh! I´m buying the next round!

Evan: ....*sigh*....
by Tankred February 04, 2011