庸碌无能

yōng lù wú néng

mediocre and incompetent

庸

yōng

ordinary

碌

lù

(bound form used in 忙碌[mang2 lu4], 勞碌|劳碌[lao2 lu4], 庸碌[yong1 lu4] etc)

无

wú

not to have

能

néng

can