口出狂言

kǒuchūkuángyán
  1. to speak conceited nonsense
  2. to come out with arrogant claptrap

CEDICT

to talk wildly and arrogantly

Wiktionary

Entry Composition

1 口 kǒu
  1. mouth
  2. classifier for things with mouths (people, domestic animals, cannons, wells etc)
  3. classifier for bites or mouthfuls
=2 出 chū
  1. to go out; to come out
  2. to arise; to occur
  3. to produce; to yield
  4. to go beyond; to exceed
  5. (used after a verb to indicate an outward direction or a positive result)
  6. classifier for dramas, plays, operas etc
=2 出 chū variant of 出 chū (classifier for plays or chapters of classical novels)
3 狂言 kuángyán
  1. ravings
  2. delirious utterances
  3. kyōgen (a form of traditional Japanese comic theater)