Defeat, overcome (7)
I believe the answer is:
conquer
I believe this clue is a double definition.
'defeat' is the first definition.
(to conquer is to defeat or beat)
'overcome' is the second definition.
(conquering is a kind of overcoming)
(Other definitions for conquer that I've seen before include "worst" , "Be victorious" , "Capture by force" , "Best" , "Beat" .)