Pressed on in anger with Democrat (6)
I believe the answer is:
ironed
'pressed' is the definition.
(similar in meaning)
'on in anger with democrat' is the wordplay.
'in' is an insertion indicator.
'anger' becomes 'ire' (ire is intense rage).
'with' says to put letters next to each other.
'democrat' becomes 'd'.
'on' inserted within 'ire' is 'irone'.
'irone'+'d'='IRONED'
(Other definitions for ironed that I've seen before include "Smoothed with hot metal" , "Had an evening out" , "Made smooth, shirt or collar" , "De Niro (anag)" , "Pressed and smoothed" .)