Opposed to getting soft with a rival (9)
I believe the answer is:
contender
'rival' is the definition.
(I know that rival can be written as contender)
'opposed to getting soft' is the wordplay.
'opposed to' becomes 'con' (as in pros and cons).
'getting' says to put letters next to each other.
'soft' becomes 'tender' (similar in meaning).
'con'+'tender'='CONTENDER'
'with a' is the link.
(Other definitions for contender that I've seen before include "One striving" , "One fighting others (for something)" , "Struggler in rivalry" , "One who strives" , "One struggling" .)