In love with awful Unionist, dear me no! (9)
I believe the answer is:
enamoured
'in love' is the definition.
(I've seen this before)
'awful unionist dear me no' is the wordplay.
'awful' indicates anagramming the letters.
'unionist' becomes 'u' (abbreviation as in Democratic Unionist Party).
'u'+'dear'+'me'+'no'='udearmeno'
'udearmeno' anagrammed gives 'ENAMOURED'.
'with' acts as a link.
(Other definitions for enamoured that I've seen before include "Greatly taken with" , "Our mean Ed (anag.)" , "Inspired with love" , "In love with - named rou (anag)" , "Filled with love" .)