The chap to shoot is a tyrant! (6)
I believe the answer is:
despot
'tyrant' is the definition.
(I know that tyrant can be written as despot)
'the chap to shoot' is the wordplay.
'the chap' becomes 'des' ().
'to shoot' becomes 'pot' (I've seen this in other clues).
'des'+'pot'='DESPOT'
'is a' acts as a link.
(Other definitions for despot that I've seen before include "One exploiting rule" , "Posted to tryant" , "who treats others badly?" , "Person with more than enough power" , "Cruel absolute ruler" .)