na-adjective
sleepy-looking; sleepy-sounding
Describes someone or something that appears or sounds sleepy. Often used with 〜な, 〜に, or 〜だ.
彼は眠そうな顔をしている。
He has a sleepy look on his face.
眠そうな声で「おはよう」と言った。
He said 'good morning' in a sleepy-sounding voice.