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to sleep (lying down)
to go to bed; to lie in bed
to lie down
to lie flat (e.g. of hair)
to lie idle (of funds, stock, etc.)
to sleep (with someone, i.e. have intercourse)
to ferment (of soy sauce, miso, etc.)
疲れたから早く寐なさい。
You're tired, so go to sleep.
赤ちゃんがぐっすり寐ている。
The baby is sleeping soundly.
疲れていたので昨日は十時間も寐てしまった。
I was so tired that I ended up sleeping ten hours yesterday.