Secret love is nearby (5,2)
I believe the answer is:
close to
'nearby' is the definition.
(I've seen this in another clue)
'secret love' is the wordplay.
'secret' becomes 'closet' (synonyms).
'love' becomes 'o' (love means zero in tennis).
'closet'+'o'='CLOSE TO'
'is' acts as a link.
(Other definitions for close to that I've seen before include "near" , "'Nearby (5,2)'" , "Nearly" .)