Either way, woman's not denying love affair (5)
I believe the answer is:
Here is my best explanation:
'affair' is the definition.
'either way woman's not denying love' is the subsidiary indication.
'either way woman' becomes 'eve' (palindromic woman's name).
'denying' is a deletion indicator.
'love' becomes 'o' (In tennis, 'love' means 'zero').
'not' with 'o' taken out is 'nt'.
(Other definitions for event that I've seen before include "High jump, say", "Thing that happens", "'Occurrence, happening (5)'", "Incident, occurrence", "episode", "Incident - final outcome", "Happening, noteworthy perhaps", "400 metres?", "horse-riding competition" and "ride competitively".)