Dance with one chorus is bright (9)
I believe the answer is:
promising
'bright' is the definition.
(I know that bright can be written as promising)
'dance with one chorus' is the wordplay.
'dance' becomes 'prom' (prom is a kind of dance).
'with' means one lot of letters go next to another.
'one' becomes 'i' (Roman numeral).
'chorus' becomes 'sing' (to chorus is to sing in chorus).
'prom'+'i'+'sing'='PROMISING'
'is' acts as a link.
(Other definitions for promising that I've seen before include "Encouraging" , "Favourable -- hopeful" , "Giving one's word" , "Showing great potential" .)