Awkward Eastern doctor has to tweet under curtain (12)
I believe the answer is:
embarrassing
'awkward' is the definition.
(synonyms)
'eastern doctor has to tweet under curtain' is the wordplay.
'eastern' becomes 'e'.
'doctor has' becomes 'mb' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'to tweet' becomes 'sing' (birdsong may be tweeted).
'under' is a charade indicator (letters next to each other).
'curtain' becomes 'arras' (wall hanging acting as a curtain).
'sing' put after 'arras' is 'arrassing'.
'e'+'mb'+'arrassing'='EMBARRASSING'
(Other definitions for embarrassing that I've seen before include "Causing to feel shame" , "Causing one to feel awkward" , "Socially very awkward" , "Humiliating" , "Blush-making" .)