This is what you call someone when they constantly lie about anything and everything that comes out of their mouth. It doesn't even make sense for them to lie about something but they do anyway. This may be to "fit in" or just "be cool."
1. Roman: Yeah I just won the halfpipe competition up at ski roundtop last weekend.
Alec: Yeah i won a competition one time when i lived back in Alaska.
Anthony (to Alec): You're a Deetz.
2. Ramsey: I had a threesome last night with those two girls.
Ian: I had sex with both of those girls before, and i've already been in three threesomes.
(Ian walks away)
Anthony (to Ramsey): He's a fuckin' deetz!