Outcome is not odd when looked at over time (5)
I believe the answer is:
event
'outcome' is the definition.
(I know that outcome can be written as event)
'not odd when looked at over time' is the wordplay.
'not odd' becomes 'even' ('even' is the opposite to 'odd').
'when looked at over' means one lot of letters go next to another (some letters go over or above others).
'time' becomes 't' (abbreviation).
'even'+'t'='EVENT'
'is' acts as a link.
(Other definitions for event that I've seen before include "Something taking place" , "A noteworthy happening or occurrence" , "Fixture" , "Thing that happens" , "Something happening" .)