potshot
Concise Oxford English Dictionary © 2008 Oxford University Press:
potshot/ˈpɒtʃɒt/
▶noun
- 1 a shot aimed unexpectedly or at random.
■ a shot at a game bird or other animal made without regard to hunting rules.
- 2 a random attack or criticism.
– origin C19: orig. a shot at an animal intended for the pot, i.e. for food, rather than for display (which would require skilled shooting).
'potshot' also found in these Oxford entries:

