Love quiet American work (4)
I believe the answer is:
opus
'work' is the definition.
(I've seen this before)
'love quiet american' is the wordplay.
'love' becomes 'o' (In tennis, 'love' means 'zero').
'quiet' becomes 'p' (music symbol for 'piano').
'american' becomes 'us'.
'o'+'p'+'us'='OPUS'
(Other definitions for opus that I've seen before include "Soup (anag.)" , "Musical piece" , "Musical composition in the soup" , "Major work" , "Work of 25 perhaps" .)