shoot your mouth off
US /ʃuːt jʊər maʊθ ɔːf/
UK /ʃuːt jʊər maʊθ ɔːf/

1.
nói huyên thuyên, nói bô bô
to talk too much, especially in a boastful or indiscreet way
:
•
He tends to shoot his mouth off after a few drinks.
Anh ấy có xu hướng nói huyên thuyên sau vài ly.
•
Don't shoot your mouth off about the surprise party.
Đừng nói huyên thuyên về bữa tiệc bất ngờ.