Well-matched (4)
I believe the answer is:
even
'well-matched' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for even that I've seen before include "time of day" , "Like 2, 4 or 6, say" , "Like 2018 but not 2017" , "Plumb" , "Peaceful" .)