One losing love receives morning call (4)
I believe the answer is:
name
'call' is the definition.
(synonyms)
'one losing love receives morning' is the wordplay.
'losing' indicates named letters should be taken away.
'love' becomes 'o' (love means zero in tennis).
'receives' is an insertion indicator (inserted letters are received).
'morning' becomes 'am'.
'one' with 'o' taken away is 'ne'.
'ne' going around 'am' is 'NAME'.
(Other definitions for name that I've seen before include "Appoint - famous person" , "Call; reputation" , "Famous person; reputation" , "Identification" , "Good reputation; specify; christen" .)