Spring approaching? Nearly (4-4)
I believe the answer is:
well-nigh
'nearly' is the definition.
(I know that nearly can be written as well-nigh)
'spring approaching?' is the wordplay.
'spring' becomes 'well' (both can mean a source of water).
'approaching?' becomes 'nigh' (as in 'the end is nigh').
'well'+'nigh'='WELL-NIGH'
(Other definitions for well-nigh that I've seen before include "Healthy plus near = almost" , "Amost, very nearly" .)