Over time, quits competitions (6)
I believe the answer is:
events
'competitions' is the definition.
(I've seen this before)
'over time quits' is the wordplay.
'over' indicates putting letters inside.
'time' becomes 't'.
'quits' becomes 'evens' (I've seen this before).
't' placed inside 'evens' is 'EVENTS'.
(Other definitions for events that I've seen before include "Noteworthy happenings" , "They take place" , "Important happenings for Steven" , "Horse-riding competitions" , "races?" .)