Wall - A partition wall; in Ezekiel 13:12, the word used is the usual word for the outer wall of a house or city. The fall of the partition wall would perhaps involve the fall of the whole house.
Untempered morter - Or, whited plaster, employed to patch up a wall, so as to give it an appearance (without the reality) of strength and beauty. Compare Matthew 23:27. In the original there is a play upon a word rendered “folly” in Jeremiah 23:13.