我利勉[gariben] drudge
俄勉強[niwakabenkyou] cramming
勉める[tsutomeru] to endeavor (endeavour)
勤勉[kinben] diligent
刻苦勉励[kokkubenrei] being arduous

試験勉強[shikenbenkyou] cramming for exams
勉めて[tsutomete] as much as possible
不勉強[fubenkyou] idleness
勉学[bengaku] study
勉強[benkyou] study