Dictator's rival with talent for reasonableness (9)
I believe the answer is:
viability
'reasonableness' is the definition.
The answer and definition can be both human attributes as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'dictator's rival with talent' is the wordplay.
'dictator's rival' becomes 'vi' (I am not sure about this - if you are sure you should believe this answer much more).
'with' says to put letters next to each other.
'talent' becomes 'ability' (I've seen this in another clue).
'vi'+'ability'='VIABILITY'
'for' acts as a link.
Can you help me to learn more?
(Other definitions for viability that I've seen before include "likelihood of success" , "Aptitude for living" .)