1To be disheartened or dejected; to look or feel very discouraged.
試験に落ちて彼はげっそりしていた。
He looked very dejected after failing the exam.
発表がうまくいかず、メンバー全員がげっそりした。
The presentation went poorly and all the members were disheartened.
2To suddenly lose a lot of weight; to look emaciated or very thin (often due to illness or stress).
入院してから彼はげっそり痩せた。
Since being hospitalized he has lost a lot of weight.
病気でげっそりした顔つきになっている。
They look emaciated from illness.