kick somebody when they're down

kick (one) when (one) is down

To criticize, exploit, insult, or otherwise treat badly one who has already suffered a setback or is in a vulnerable position. Can Jeff's employee review wait until next week? His girlfriend just left him, and I don't want to kick him while he's down. A: "I'm sorry you got fired, but you shouldn't have been so sloppy with your work." B: "Wow, way to kick me when I'm down."
See also: down, kick
Farlex Dictionary of Idioms.

kick somebody when they’re ˈdown

continue to hurt somebody when they are already defeated, etc: George generally believed that you should never kick a man when he’s down, but thought that this time he might make an exception.
See also: down, kick, somebody
Farlex Partner Idioms Dictionary
See also:
  • hit (one) when (one) is down
  • hit somebody when they're down
  • kick (one) when (one) is down
  • kick someone when they are down
  • kick (one) in the teeth
  • kick somebody in the teeth
  • kick someone in the teeth
  • fire questions, insults, etc. at somebody
  • fire insults at (one)
  • hurl insults (at one)