Golf club missing top and side (4)
I believe the answer is:
edge
'side' is the definition.
(I know that edge is a type of side)
'golf club missing top' is the wordplay.
'golf club' becomes 'wedge' (type of golf club).
'missing top' means to remove the first letter.
'wedge' with its initial letter removed is 'EDGE'.
'and' acts as a link.
(Other definitions for edge that I've seen before include "Sharp ridge" , "The part farthest from the middle" , "Move little by little to the border" , "Bite" , "Periphery" .)