Inadequacy of right in demise (6)
I believe the answer is:
dearth
'inadequacy' is the definition.
(I know that dearth is a type of scarceness)
'right in demise' is the wordplay.
'right' becomes 'r' (common abbreviation).
'in' indicates putting letters inside.
'demise' becomes 'death' (synonyms).
'r' going within 'death' is 'DEARTH'.
'of' is the link.
(Other definitions for dearth that I've seen before include "Scarcity - famine" , "deficiency" , "Acute insufficiency" , "Lack of resources" , "Acute shortage" .)