Wayward ranter raving (6)
I believe the answer is:
errant
'wayward' is the definition.
(I've seen this before)
'ranter raving' is the wordplay.
'raving' indicates an anagram.
'ranter' anagrammed gives 'ERRANT'.
(Other definitions for errant that I've seen before include "looking for adventure" , "Offending" , "like Don Quixote?" , "so some knights are called" , "Rambling" .)