虛有其表

虚有其表
yǒubiǎo
  1. looks impressive but is worthless (idiom)
  2. not as good as it looks
  3. a reputation with no substance

CEDICT

to look impressive but lack real worth

Wiktionary

雜錄》:「器重,……,……退:『虛有其表。』」用以形容華麗外表實際內涵

重編國語辭典

用以形容華麗外表實際內涵

維基詞典

Entry Composition