Ready, mature (4)
I believe the answer is:
ripe
I believe this clue is a double definition.
'ready' is the first definition.
(similar in meaning)
'mature' is the second definition.
(I know that mature can be written as ripe)
(Other definitions for ripe that I've seen before include "Strong-smelling" , "Ready for picking" , "Seasoned, fully grown" , "Opportune" , "Ready to pick" .)