No objection certificate raised by Bill’s candidate (9)

I believe the answer is:

contender

I'm a little stuck... Click here to teach me more about this clue!

'candidate' is the definition.
(I've seen this before)

I don't understand how the remainder of the clue works.

(Other definitions for contender that I've seen before include "One striving" , "one in the field" , "No red cent (anag.)" , "One who strives" , "Candidate" .)

I've seen this clue in The Hindu.

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