US author twitching, using words rhythmically? (6)
I believe the answer is:
poetic
'using words rhythmically?' is the definition.
(poetry has rhythm)
'us author twitching' is the wordplay.
'us author' becomes 'Poe' (Edgar Allan Poe).
'twitching' becomes 'tic' (tic is a kind of twitching).
'poe'+'tic'='POETIC'
(Other definitions for poetic that I've seen before include "Flowery" , "One sort of licence" , "Expressed in verse" , "Characterised by romantic imagery" , "Ice pot (anag.)" .)