unsportsmanlike
adjective /ˌʌnˈspɔːtsmənlaɪk/
  /ˌʌnˈspɔːrtsmənlaɪk/
(disapproving)- not behaving in a fair, generous and polite way, especially when playing a sport or game
- unsportsmanlike conduct
 
Oxford Collocations DictionaryUnsportsmanlike is used with these nouns:- conduct