Despite common belief that considers it as an appetizer preceding the main course, in Italian restaurants actually it is a kind of dish which forces you to reject the rest of food you've already ordered.
As an accurate analysis of the word reveals, the prefix is not "ante" which means "before" (as in other Italian words "anteprima"= "preview" or "antenato"="forefather"), but is "anti" which means "against" (as in the Italian words "antifascista"="antifascist" or "anticlericale"="anticlerical")
Therefore the real meaning of the word is *"antimeal" or "against the meal"
Waiter: Good evening, have you already seen what's on the menu?
Customer: Yes, I'd like an antipasto, please.
Waiter: Good choice! And then, what else?
Customer: Don't you understand what I'm saying?! I don't wanna eat your fucking food!