An intransitive verb meaning to be half-asleep or groggy — to act or think unclearly because one hasn't fully woken up.
朝、寝ぼけて靴を左右逆に履いて出かけてしまった。
In the morning I was half-asleep and went out wearing my shoes on the wrong feet.
彼は寝ぼけて誰にでも怒鳴っていた。
He was half-asleep and yelled at everyone.
夜中に電話で起こされて、しばらく寝ぼけていた。
I was woken by a phone call in the middle of the night and stayed groggy for a while.