a wolf in sheep's clothing
US /ə wʊlf ɪn ʃiːps ˈkloʊðɪŋ/
UK /ə wʊlf ɪn ʃiːps ˈkloʊðɪŋ/

1.
양의 탈을 쓴 늑대
a person who appears friendly or harmless but is actually dangerous or malicious
:
•
Be careful of him; he's a wolf in sheep's clothing.
그를 조심해; 그는 양의 탈을 쓴 늑대야.
•
The new manager seemed nice at first, but he turned out to be a wolf in sheep's clothing.
새로운 매니저는 처음에는 친절해 보였지만, 그는 양의 탈을 쓴 늑대로 드러났다.