嘴上没毛,办事不牢

zuǐ shàng méi máo , bàn shì bù láo

a youth without facial hair cannot be relied upon (proverb)

zuǐ

mouth

shàng

(bound form) up; upper; above; previous

méi

(negative prefix for verbs) have not; not

máo

hair

,

bàn

to take care of (a matter); to deal with (a task, procedure etc); to organize (an event)

shì

matter

no; not so

láo

firm