Dancing until dark (5)
I believe the answer is:
unlit
'dark' is the definition.
(similar in meaning)
'dancing until' is the wordplay.
'dancing' is an anagram indicator.
'until' with letters rearranged gives 'UNLIT'.
(Other definitions for unlit that I've seen before include "not exactly bright" , "Perhaps invisible" , "Not yet burning" , "such as dark alley?" , "Not illuminated" .)