固若金汤 gù ruò jīn tāng

DEFINITIONS

  1. secure as a city protected by a wall of metal and a moat of boiling water (idiom)
  2. well fortified
  3. invulnerable to attack

CHARACTERS

固 gù to become solid, solidify; strength
若 ruò if, supposing, assuming; similar
金 jīn gold; metals in general; money
汤 tāng hot water; soup, gravy, broth