Friend holds a key ring (4)
I believe the answer is:
peal
'ring' is the definition.
('peal' can be a synonym of 'ring')
'friend holds a key' is the wordplay.
'friend' becomes 'pal' (pal is a kind of friend).
'holds' indicates putting letters inside.
'a key' becomes 'e' (I've seen this in other clues).
'pal' going around 'e' is 'PEAL'.
(Other definitions for peal that I've seen before include "Set of church bells" , "Ring (of bell), clap (of thunder)" , "Sound of bells, thunder" , "(Bells) ring" , "Sound of bells or laughter" .)