人不可貌相

rénbùkěmàoxiàng
  1. you can't judge a person by appearance (idiom)
  2. you can't judge a book by its cover
  3. often in combination 人不可貌相，海水不可斗量 rénbùkěmàoxiàng,hǎishuǐbùkědǒuliáng

CEDICT

one cannot judge someone by his or her appearance; you can’t judge a book by its cover

Wiktionary

Entry Composition

1 人 rén person; people

classifiers: 個, 位
2 不可 bùkě cannot; should not; must not
3 貌相 màoxiàng
  1. appearance (esp. superficial)
  2. looks
  3. to judge a person by appearances

Containing this entry

人不可貌相，海水不可斗量 rénbùkěmàoxiàng,hǎishuǐbùkědǒuliáng you can't judge a person by appearance, just as you can't measure the sea with a pint pot (idiom)