Rival offer pursuing deception (9)
I believe the answer is:
contender
'rival' is the definition.
(I know that rival can be written as contender)
'offer pursuing deception' is the wordplay.
'offer' becomes 'tender' (tender can mean to offer something).
'pursuing' is a charade indicator (letters next to each other).
'deception' becomes 'con' (a con is a trick or deception).
'tender' after 'con' is 'CONTENDER'.
(Other definitions for contender that I've seen before include "One fighting others (for something)" , "One seeking title" , "Competitor, challenger" , "One striving" , "one in the field" .)