Night without end - almost (4)
I believe the answer is:
nigh
'almost' is the definition.
(nigh can mean almost or nearly)
'night without end' is the wordplay.
'without end' means to remove the last letter.
'night' with its last letter taken off is 'NIGH'.
(Other definitions for nigh that I've seen before include "All but one" , "See 23" , "Just round the corner" , "Near (poetic)" , "Nearby" .)