Grew up and found a mate on the outskirts of an ancient city (7)
I believe the answer is:
matured
'grew up' is the definition.
(to grow up is to mature)
'found a mate on the outskirts of an ancient city' is the wordplay.
'found a mate' becomes 'mated' (I can't explain this - if you can you should give a lot more credence to this answer).
'on the outskirts of' indicates putting letters inside.
'an ancient city' becomes 'ur' (ancient Sumerian city state).
'mated' going around 'ur' is 'MATURED'.
'and' is the link.
Can you help me to learn more?
(Other definitions for matured that I've seen before include "Ripened" , "Became fully ripe" , "Developed fully" , "Mellowed" , "Developed; grew up" .)