Antosym

Two words can be the antosym of eachother. For example, If I was playing basketball and I hit someone with a nasty crossover, a fan could shout "Damn that move was dirty!" one could also shout "Damn that move was clean". Clean and Dirty are antonyms, however, in that context they mean the same thing. Thus the word antosym, two words that mean the opposite thing but in certain contexts, mean the same.