Maverick outlay got necessary requirement, say (9)
'necessary requirement say' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'maverick outlay got' is the wordplay.
'maverick' indicates anagramming the letters.
'outlaygot' with letters rearranged gives 'TAUTOLOGY'.
Can you help me to learn more?
(Other definitions for tautology that I've seen before include "Use of words repeating something already implied", "as new innovation, perhaps", "identifying myself personally?", "Unnecessary repetition of words", "Repetition in different words for a gouty lot".)