酷しい[ikameshii] severe
厳酷[genkoku] severity
酷なやり方[kokunayarikata] cruel deed
酷寒[kokkan] severe (intense) cold
酷刑[kokkei] severe punishment

酷使[kokushi] exploitation
酷似[kokuji] resemblance
酷暑[kokusho] intense heat
酷税[kokuzei] heavy taxation
酷評[kokuhyou] severe criticism