Correcting fluid: line cancelled out (9)
I believe the answer is:
nullified
'cancelled out' is the definition.
(I've seen this before)
'correcting fluid line' is the wordplay.
'correcting' indicates anagramming the letters (the order of letters must be corrected).
'fluid'+'line'='fluidline'
'fluidline' with letters rearranged gives 'NULLIFIED'.
(Other definitions for nullified that I've seen before include "Abrogated" , "Scrubbed" , "revoked" , "Cancelled out" , "Made invalid" .)