咬人狗儿不露齿

yǎo rén gǒu r bù lù chǐ

lit. the dog that bites does not show its fangs (idiom)

fig. You can't tell the really dangerous enemy from his external appearance.

yǎo

variant of 咬[yao3]

rén

person; people

gǒu

dog

r

non-syllabic diminutive suffix

no; not so

dew

齿

chǐ

tooth