嘴替

zuǐtì
(slang) sb who effectively articulates others' thoughts or feelings on their behalf

CEDICT

slang

Entry Composition

1 嘴 zuǐ
  1. mouth
  2. beak
  3. nozzle
  4. spout (of teapot etc)

classifiers: 張, 個
2 替 tì
  1. to substitute for
  2. to take the place of
  3. to replace
  4. for
  5. on behalf of
  6. to stand in for