Comfortable situation for a professor (4,5)
I believe the answer is:
'a professor' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'comfortable situation' is the wordplay.
'comfortable' becomes 'easy' (similar in meaning).
'situation' becomes 'chair' (chair is a kind of situation).
'for' acts as a link.
Can you help me to learn more?
(Other definitions for easy chair that I've seen before include "Item of furniture" , "Comfortable place to relax" , "ambitious professor avoids" , "nice spot to be in" , "source of comfort" .)