Niche setter's inclined to retire? (9)
I believe the answer is:
recessive
'inclined to retire?' is the definition.
I can't tell whether this definition defines the answer.
'niche setter's' is the wordplay.
'niche' becomes 'recess' (synonyms).
'setter's' becomes 'ive' ('I've', referring to the crossword setter).
'recess'+'ive'='RECESSIVE'
Can you help me to learn more?
(Other definitions for recessive that I've seen before include "backward moving" , "Tending to go backwards" , "Tending to recede" , "Serves ice (anag)" .)