Carry on with maturity (4)
I believe the answer is:
wage
'carry on' is the definition.
(thesaurus)
'with maturity' is the wordplay.
'with' becomes 'w' (abbreviation).
'maturity' becomes 'age' (I've seen this before).
'w'+'age'='WAGE'
(Other definitions for wage that I've seen before include "Money earned" , "Salary" , "Regular pay" , "Earnings - carry on" , "conduct" .)