Cut poor decisions -- not so! (7)
I believe the answer is:
incised
'cut' is the definition.
('incised' can be similar in meaning to 'cut')
'poor decisions not so' is the wordplay.
'poor' indicates an anagram.
'not' suggests deleting specific letters.
'decisions' with 'so' removed is 'deciins'.
'deciins' anagrammed gives 'INCISED'.
(Other definitions for incised that I've seen before include "Engraved" , "Made cuts in (surface)" , "Cut (into a surface)" .)