開門揖盜

开门揖盗
kāiményīdào
leaving the door open invites the thief (idiom); to invite disaster by giving evildoers a free hand

CEDICT

to introduce bad people and bring disaster upon oneself

Wiktionary

揖，請。開門揖盜比喻引進壞人，自招禍患。

重編國語辭典

比喻引進壞人，自己招來禍患

維基詞典

Entry Composition

1 開門 kāimén
  1. to open a door (lit. and fig.)
  2. to open for business
2 揖 yī to greet by raising clasped hands
3 盜 dào
  1. to steal
  2. to rob
  3. to plunder
  4. thief
  5. bandit
  6. robber