Husband not well: is he over this? (4)
I believe the answer is:
hill
'he over this?' is the definition.
The definition suggests a singular noun which matches the answer.
'husband not well' is the wordplay.
'husband' becomes 'h' (abbreviation).
'not well' becomes 'ill' ('ill' is the opposite to 'well').
'h'+'ill'='HILL'
'is' acts as a link.
Can you help me to learn more?
(Other definitions for hill that I've seen before include "See 14" , "Elevation on land" , "pike" , "See 8" , "Mound (of mole, ants)" .)