A farewell maybe said out of love (5)
I believe the answer is:
adios
'a farewell' is the definition.
(adios is a kind of farewell)
'maybe said out of love' is the wordplay.
'maybe' is an anagram indicator.
'out of' means one lot of letters goes inside another.
'love' becomes 'o' (love means zero in tennis).
'said' is an anagram of 'adis'.
'adis' placed around 'o' is 'ADIOS'.
(Other definitions for adios that I've seen before include "Goodbye, amigo" , "Goodbye (Spanish)" , "Bye-bye (amigo)" , "Adieu, arrivederci" , "Good-bye (Sp.)" .)