Awkward pretence with what isn't actually a diamond? (9)
I believe the answer is:
shambling
'awkward' is the definition.
(shambling can mean clumsy or awkward)
'pretence with what isn't actually a diamond?' is the wordplay.
'pretence' becomes 'sham' (I've seen this before).
'with' is a charade indicator (letters next to each other).
'what isn't actually a diamond?' becomes 'bling' (bling can mean fake jewellery).
'sham'+'bling'='SHAMBLING'
(Other definitions for shambling that I've seen before include "Proceeding inefficiently" , "Shuffling along" .)