Darkness close, end of daylight (5)
I believe the answer is:
night
'darkness' is the definition.
(night is a kind of darkness)
'close end of daylight' is the wordplay.
'close' becomes 'nigh' ('nigh' can be similar in meaning to 'close'**).
'end of' says to take the final letters.
The last letter of 'daylight' is 't'.
'nigh'+'t'='NIGHT'
(Other definitions for night that I've seen before include "What proverbially follows day" , "- School, - owl" , "Thing (anag)" , "Illumination needed now" , "Saturday -- Fever (film)" .)