From Longman Dictionary of Contemporary Englishunsportingun‧sport‧ing /ʌnˈspɔːtɪŋ $ -ˈspɔːr-/ adjective behaving in an unfair way, especially towards an opponent in a game or competition
Examples from the Corpus
unsporting• It was a filthy trick, totally unsporting and certainly not cricket.• There were rival theatrical cliques, and rifts and vendettas among the games people over alleged unsporting behaviour. 