Free love with writer (4)
I believe the answer is:
open
'free' is the definition.
('open' can be similar in meaning to 'free')
'love with writer' is the wordplay.
'love' becomes 'o' (In tennis, 'love' means 'zero').
'with' means one lot of letters go next to another.
'writer' becomes 'pen' (I've seen this before).
'o'+'pen'='OPEN'
(Other definitions for open that I've seen before include "Frank; unobstructed" , "Uncovered" , "Overt" , "golf contest" , "Undo; ajar" .)