Banknotes possibly overlooked by Tory candidate (9)
I believe the answer is:
contender
'candidate' is the definition.
(I've seen this before)
'banknotes possibly overlooked by tory' is the wordplay.
'banknotes possibly' becomes 'tender' (I can't justify this - if you can you should believe this answer much more).
'overlooked by' means one lot of letters go next to another (in a down clue, some letters go above others).
'tory' becomes 'con' (abbreviation for conservative).
'tender' after 'con' is 'CONTENDER'.
Can you help me to learn more?
(Other definitions for contender that I've seen before include "Trend once (anag.)" , "Candidate" , "Struggler in rivalry" , "One striving" , "Competitor, challenger" .)