Take advantage of exit poll almost being wrong (7)
I believe the answer is:
exploit
'take advantage of' is the definition.
(synonyms)
'exit poll almost being wrong' is the wordplay.
'almost' means to remove the last letter (most of the word but not all of it).
'being wrong' indicates an anagram.
'exit'+'poll'='exitpoll'
'exitpoll' with its last letter removed is 'exitpol'.
'exitpol' anagrammed gives 'EXPLOIT'.
(Other definitions for exploit that I've seen before include "Make use of - achievement" , "Milk" , "Fleece?" , "Take advantage of - feat" , "Feat; make use of" .)