Denshi Jisho — Online Japanese dictionary

寝る ねる 1: to lie down;
2: to go to bed; to lie in bed;
3: to sleep (lying down);
4: to sleep (with someone, i.e. have intercourse);
5: to lie idle
Common word, Ichidan verb, Intransitive verb 
寝る時間 ねるじかん bedtime
Noun 
寝る子は育つ ねるこはそだつ Sleep brings up a child well
Expression, Idiomatic expression 
寝る間も惜しんで ねるまもおしんで without sparing time for sleep
Expression, Adverb 
寝る程楽は無かりけり ねるほどらくはなかりけり There is nothing better than sleeping
Expression, Idiomatic expression 

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