say a mouthful

1.  {v. phr.},  {slang}
To say something of great importance or meaning; say more by a sentence than the words usually mean. — Usually in past tense.
Tom said a mouthful when he guessed that company was coming to visit. A dozen people came.
2.  {v. phr.},  {informal}
To vent one's honest opinion, even in anger.
He sure said a mouthful when he told his boss what was wrong with our business.
Contrast: GET AN EARFUL.
Categories: anger {informal} {slang} {v. phr.}