Smitten with awful demeanour? (9)
I believe the answer is:
enamoured
'smitten' is the definition.
(I've seen this before)
'awful demeanour?' is the wordplay.
'awful' is an anagram indicator.
'demeanour' anagrammed gives 'ENAMOURED'.
'with' acts as a link.
(Other definitions for enamoured that I've seen before include "Besotted" , "Charmed" , "Greatly taken with" , "Bewitched" , "Inspired with love" .)