A plea or objection made in response to another plea, especially a statement that a charge or claim against someone is unfounded.
From counter- + please, an archaic legal term meaning 'a plea' (unrelated to modern 'please'). The word preserves medieval French legal terminology used in English courts.
The word 'please' in law came from Old French 'plaise,' meaning 'it pleases'—counterpleases were literally arguments saying 'it doesn't please us that this claim stands without answer.'
Complete word intelligence in one call. Free tier — 50 lookups/day.