Forget extract from sanctimonious review (4)
I believe the answer is:
omit
'forget' is the definition.
(thesaurus)
'extract from sanctimonious review' is the wordplay.
'extract from' says the answer is hidden in the clue (I've seen this in other clues).
'review' says the letters should be written backwards.
'timo' is hidden within 'sanctimonious'.
'timo' written backwards gives 'OMIT'.
(Other definitions for omit that I've seen before include "Leave out or exclude" , "Exclude; forget to include" , "Neglect to include" , "Exclude - neglect" , "Exclude; veto" .)