Genuine gold - at that point, twitch (9)
I believe the answer is:
authentic
'genuine' is the definition.
(similar in meaning)
'gold at that point twitch' is the wordplay.
'gold' becomes 'Au' (Au is the chemical symbol for gold).
'at that point' becomes 'then' (I've seen this in another clue).
'twitch' becomes 'tic' (tic is a kind of twitch).
'au'+'then'+'tic'='AUTHENTIC'
(Other definitions for authentic that I've seen before include "Ian, the cut is genuine" , "reliable" , "trustworthy" , "Genuine, not a copy" , "24 [LEGIT]" .)