Finished last in event, that's clear (5)
I believe the answer is:
overt
'clear' is the definition.
(both can mean apparent or obvious)
'finished last in event' is the wordplay.
'finished' becomes 'over' (similar in meaning).
'last in' indicates one should take the final letters.
The last letter of 'event' is 't'.
'over'+'t'='OVERT'
'that's' acts as a link.
(Other definitions for overt that I've seen before include "____ is able to be seen" , "This is not hard to see" , "Open and candid" , "Obvious, patent" , "Plain and obvious" .)