Literal meaning: Plywood.
Slang meaning: A person of low intelligence who is dumb, not very bright, not so smart, and generally pretty stupid.
"Dikt" can be used in place of "dumbass", except "dikt" is not offensive at all, and therefore can be used in many more situations - it's a catch-all insult.
2. D.K.T. (Each letter pronounced separately)
Toto: What a dikt!
Chen: (Drinking beer before driving)
Gilad: What are you, a D.K.T.?
Berz: (Does something stupid)
Everyone else: Diiiiiiiiiiiiiiiiiiiiiiiiiiikt...