ぐっすり

ぐっすり is an onomatopoeic adverb for deep sleep.

Common patterns

• ぐっすり眠(ねむ)る (to sleep soundly)
• ぐっすり寝(ね)る (to sleep deeply)
• ぐっすり眠(ねむ)れる (to be able to sleep well)

Similar words

• ぐっすり (soundly, deeply)
• すやすや (peacefully - often for babies)
• ぐーぐー (snoring sounds, sleeping)
• ころっと寝(ね)る (to fall asleep easily)

Note: This is a mimetic word (擬態語(ぎたいご)) expressing a state rather than a sound.