Out until dark (5)
I believe the answer is:
unlit
'dark' is the definition.
('unlit' can be similar in meaning to 'dark')
'out until' is the wordplay.
'out' indicates anagramming the letters.
'until' is an anagram of 'UNLIT'.
(Other definitions for unlit that I've seen before include "Perhaps invisible" , "Without illumination" , "such as dark alley?" , "Left in the dark" , "Lacking illumination" .)