Cut tax — easy? Not entirely (3)
I believe the answer is:
axe
'cut' is the definition.
(I've seen this before)
'tax easy? not entirely' is the wordplay.
'not entirely' indicates the answer is hidden within the clue.
'AXE' is hidden in the letters of 'tax easy'.
(Other definitions for axe that I've seen before include "Chopping tool with heavy blade" , "Abandon project with chopping tool" , "Fire weapon" , "fell" , "Get rid of" .)