Defender on the floor, stop attacking (4,4)
I believe the answer is:
back down
'stop attacking' is the definition.
'defender on the floor' is the wordplay.
'defender' becomes 'back' (I've seen this in other clues).
'on' says to put letters next to each other.
'the floor' becomes 'down' (I've seen this before).
'back'+'down'='BACK DOWN'
(Other definitions for back down that I've seen before include "being in lower division once more?" , "Withdraw argument in face of opposition" , "Give up claim or withdraw argument" , "Withdraw argument or avoid confrontation" , "Withdraw challenge" .)