Dolphin’s limb (7)
I believe the answer is:
flipper
'dolphin's limb' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for flipper that I've seen before include "Dolphin's limb" , "Aquatic animal's fin" , "feature of dolphin?" , "Before the game, the referee perhaps makes" , "Swimmer's foot gear" .)