A farewell said distractedly out of love (5)
I believe the answer is:
adios
'a farewell' is the definition.
(I know that adios is a type of farewell)
'said distractedly out of love' is the wordplay.
'distractedly' indicates an anagram.
'out of' means one lot of letters goes inside another (some letters on the outside of others).
'love' becomes 'o' (love means zero in tennis).
'said' with letters rearranged gives 'adis'.
'adis' enclosing 'o' is 'ADIOS'.
(Other definitions for adios that I've seen before include "Goodbye (Spanish)" , "Farewell amigo!" , "so long in Mexico" , "Goodbye to Spain" , "Goodbye (20 across)" .)