Значение идиомы shoot off one’s mouth

[shoot off one’s mouth] or [shoot off one’s face] {v. phr.},{slang} To give opinions without knowing all the facts; talk as if youknow everything.

Tom has never been to Florida, but he’s alwaysshooting his mouth off about how superior Florida is to California.

I want to study the problem before I shoot off my face.

Theeditor of the newspaper is always shooting his mouth off about thetrouble in Africa.