Poet's mature association with nature? (3,5)
I believe the answer is:
eye rhyme
'poet's' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
I don't understand how the remainder of the clue works.
(Other definitions for eye rhyme that I've seen before include "For example know how" , "Keats and Yeats, for example" , "shy?" , "Love and move eg" , "scan piece of poetry" .)