裡應外合 lǐ yìng wài hé

DEFINITIONS

  1. to coordinate outside and inside offensives (idiom)
  2. (fig.) to act together

CHARACTERS

裡 lǐ inside, interior, within
應 yìng should, ought to, must
外 wài
HSK 2
out, outside, external; foreign
合 hé
HSK 4
combine, unite, join; gather