Some swell night? Almost (4-4)
I believe the answer is:
well-nigh
'almost' is the definition.
('well-nigh' can be a synonym of 'almost')
'some swell night?' is the subsidiary indication.
'some' indicates a hidden word (Some of the parts of the word are used).
'wellnigh' can be found hidden inside 'swell night'.
(Other definitions for well-nigh that I've seen before include "Amost, very nearly" , "Healthy plus near = almost" .)