Good Dickens character showing resentment (6)
I believe the answer is:
grudge
'resentment' is the definition.
(grudge is a kind of resentment)
'good dickens character' is the wordplay.
'good' becomes 'g' (abbreviation).
'dickens character' becomes 'rudge' (I've seen this before).
'g'+'rudge'='GRUDGE'
'showing' acts as a link.
(Other definitions for grudge that I've seen before include "Resentment, animosity" , "Persistent feeling of resentment" , "Resentment, rancour" , "Feeling of resentment or illwill" , "Envy or bad feeling towards" .)