What does 熟睡 mean?
熟睡 is a Japanese noun meaning “deep sleep; sound sleep; profound sleep” in English. It is written as 熟睡 in kanji, じゅくすい in hiragana, and jukusui in romaji. This word is part of JLPT N2 vocabulary.
Example sentence
彼女が熟睡しているのを確かめて、彼はこっそり部屋を抜け出して行った。
After making sure she was sound asleep, he crept out of the room and set off.