Liberal apprehended by one in the dark (5)
I believe the answer is:
unlit
'in the dark' is the definition.
(I've seen this before)
'liberal apprehended by one' is the wordplay.
'liberal' becomes 'l' (abbreviation).
'apprehended by' indicates putting letters inside (I've seen this in other clues).
'one' becomes 'unit' ('unit' can be a synonym of 'one').
'l' inserted inside 'unit' is 'UNLIT'.
(Other definitions for unlit that I've seen before include "Dark, gloomy" , "Shady" , "Lacking illumination" , "Not yet fired up" , "Shadowy" .)