Friend married needs hand (4)
I believe the answer is:
palm
'hand' is the definition.
(I know that hand can be written as palm)
'friend married' is the wordplay.
'friend' becomes 'pal' (pal can mean a friend).
'married' becomes 'm'.
'pal'+'m'='PALM'
'needs' is the link.
(Other definitions for palm that I've seen before include "Conceal magician" , ""trophy"" , "Use hand" , "Leaf in part of the hand?" , "Tropical tree with large leaves" .)