not say boo to a goose
US /nɑt seɪ buː tu ə ɡuːs/
UK /nɑt seɪ buː tu ə ɡuːs/

1.
tidak berani bersuara, sangat pemalu
to be very shy and quiet, and unable to speak to people you do not know
:
•
She's so timid, she wouldn't say boo to a goose.
Dia sangat pemalu, dia tidak akan berani bersuara.
•
Despite his tough appearance, he wouldn't say boo to a goose in real life.
Walaupun penampilannya garang, dia tidak akan berani bersuara dalam kehidupan sebenar.