Swear, the way things go without love (5)
I believe the answer is:
curse
'swear' is the definition.
('curse' can be a synonym of 'swear')
'the way things go without love' is the wordplay.
'the way things go' becomes 'course'.
'without' indicates named letters should be taken away.
'love' becomes 'o' (In tennis, 'love' means 'zero').
'course' with 'o' taken away is 'CURSE'.
(Other definitions for curse that I've seen before include "Invoke evil upon" , "Evil spell - oath" , "Excommunication" , "Imprecation or oath" , "Execration" .)