chī bǎo le fàn chēng de
having nothing better to do
see 吃飽撐著|吃饱撑着
吃
chī
variant of 吃[chi1]
饱
bǎo
to eat till full
了
le
(completed action marker)
饭
fàn
cooked rice
撑
chēng
to support
的
de
of; ~'s (possessive particle)