Impeached accepting Republican is loathsome (8)
I believe the answer is:
accursed
'loathsome' is the definition.
(both can mean hated)
'impeached accepting republican' is the wordplay.
'impeached' becomes 'accused' ('accuse' can be a synonym of 'impeach').
'accepting' is an insertion indicator (inserted letters are accepted).
'republican' becomes 'r' (abbreviation).
'accused' going around 'r' is 'ACCURSED'.
'is' is the link.
(Other definitions for accursed that I've seen before include "Cue cards (anag) - doomed" , "Damned" , "Goddamn" , "Wretched" , "Hateful" .)