omae wa kichigai de saitei da

[Jacob]

omae wa kichigai de saitei da: Please include your question in the post itself (Flaminius).

What does this mean? Someone said it to me in an IM. I'd attempt a translation but I have absolutely no knowledge of Japanese.

Thanks.

 

[Flaminius]

It means, "You are crazy and terrible."

omae-wa: derogatory you + topic marker (you are)
kichigai-de: crazy + beAnd (are crazy and)
saitei-da: worst + be (are worst).

 

[Aoyama]

Another variation could be : "you're nuts and obnoxious" (nothing nice, to be frank).
Barely nothing to add to Flam breaking down explanation. Just a wee little thing : saitei literally means "the lowest (worst)", it has originally a very strong meaning, but young people use it now quite often,as "terrible, bad, troublesome", not as strong as it sounds.