Not well in, is to sit between two Democrats (10)
I believe the answer is:
indisposed
'not well' is the definition.
Both the answer and definition are adjectives. Perhaps they are linked in a way I don't understand?
'in is to sit between two democrats' is the wordplay.
'two democrats' can mean two replacements for 'democrat'.
'to sit' becomes 'pose' (as in sitting for a painter).
'between' is an insertion indicator.
'democrat' becomes 'd'.
'democrat' becomes 'd'.
'is'+'pose'='ispose'
'd'+'d'='dd'
'ispose' placed inside 'dd' is 'disposed'.
'in'+'disposed'='INDISPOSED'
Can you help me to learn more?
(Other definitions for indisposed that I've seen before include "Out of sorts" , "Poorly" , "Slightly unwell" .)