The actual meaning is a dress from a greek origin however in slang terms it is an offence.

Grecian - to look like a llama or alpaca species
Tard- idiot
Girl 1: hey that guy looks like a llama dont you think?
Girl 2: yeah he kinda does, i have heard he is such an idiot
Girl 1: well then i guess he is a grecian tard
by WillCollins April 7, 2010
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