吃饱撑着
chī​bǎo​chēng​zhe

having nothing better to do

  1. 吃饱 吃飽 chī​bǎo verb + adjective
    to eat one's fill
    To eat until full; to have eaten enough.
  2. 撑 撐 chēng
    to be stuffed
    to fill to the bursting point; to feel uncomfortably full from eating too much
  3. 着 著 zhe particle
    [continuous]
    Shows that an action is currently happening or that a state is continuing; often appears before a second verb to show how the second action is being done.