熟々[tsukuzuku] completely
円熟[enjuku] ripeness
黄熟[koujuku] ripening and turning yellow
噛熟す[kamikonasu] to chew
完熟[kanjuku] completely ripe or mature

使い熟す[tsukaikonasu] to handle (men)
四字熟語[yojijukugo] four-character idiomatic compounds
修熟[shuujuku] developing skill
習熟[shuujuku] skilled
熟す[jukusu] to ripen

悪習[akushuu] bad habit
悪習慣[akushuukan] bad habit
演習[enshuu] practice
演習問題[enshuumondai] practice problem
演奏練習[ensourenshuu] musical rehearsal

学習[gakushuu] study
学習者[gakushuusha] learner
学習塾[gakushuujuku] private night-school
学習用[gakushuuyou] tutorial
学習用ヘルプ[gakushuuyouherupu] tutorial help