also: ぐうすか
adverb
sleeping soundly; sleeping like a log
Onomatopoeic adverb describing deep, undisturbed sleep. Often used with verbs like 寝る or 眠る.
疲れていたので、ぐーすか寝てしまった。
I was so tired that I slept like a log.
隣の部屋からぐーすかという寝息が聞こえる。
I can hear the sound of someone sleeping soundly from the next room.