Club with shallow sides has advantage (4,5)
I believe the answer is:
sand wedge
'club' is the definition.
(sand wedge is a kind of club)
'with shallow sides has advantage' is the wordplay.
I cannot really understand how this works, but
'with' could be 'and' and 'and' is found in the answer.
'advantage' could be 'edge' (having the edge is having an advantage) and 'edge' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Another definition for sand wedge that I've seen is " Golf club".)