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

1.
kimseye sesini çıkarmaz, çok çekingen olmak
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.
O kadar çekingen ki, kimseye sesini çıkarmaz.
•
Despite his tough appearance, he wouldn't say boo to a goose in real life.
Sert görünüşüne rağmen, gerçek hayatta kimseye sesini çıkarmaz.