A yurt Tim repaired, showing quality of an adult (8)
I believe the answer is:
maturity
'quality of an adult' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
'a yurt tim repaired' is the wordplay.
'repaired' indicates an anagram.
'a'+'yurt'+'tim'='ayurttim'
'ayurttim' with letters rearranged gives 'MATURITY'.
'showing' is the link.
Can you help me to learn more?
(Other definitions for maturity that I've seen before include "State of having reached full development" , "Full-grown state" , "age" , "State of full growth or adulthood" , "Fool" .)