[adverb] [not gradable](figurative informal) Dez likes football but he plays dirty (= unfairly).(UK and ANZ slang) Dirty great/big means extremely large.The puppy turned out to be a dirty great rottweiler.There was a dirty big hole in the middle of a road.
DIRTY
Meaning of DIRTY in English
Cambridge English vocab. Кембриджский английский словарь. 2012