Reward partners with answer during contest (10)
I believe the answer is:
compensate
'reward' is the definition.
(thesaurus)
'partners with answer during contest' is the wordplay.
'partners' becomes 'ns'.
'with' means one lot of letters go next to another.
'answer' becomes 'a' (abbreviation eg in Q and A).
'during' indicates putting letters inside.
'contest' becomes 'compete' (I've seen this before).
'ns'+'a'='nsa'
'nsa' going inside 'compete' is 'COMPENSATE'.
(Other definitions for compensate that I've seen before include "attempt to limit damage" , "Make good" , "Make financial amends to" , "Reimburse" , "Balance" .)