Unqualified, say, in cacti or bananas (9)
I believe the answer is:
categoric
'unqualified' is the definition.
(similar in meaning)
'say in cacti or bananas' is the wordplay.
'say' becomes 'eg' (both can mean 'for example').
'in' means one lot of letters goes inside another.
'bananas' indicates an anagram (informal term for mad).
'cacti'+'or'='cactior'
'cactior' anagrammed gives 'catoric'.
'eg' inserted within 'catoric' is 'CATEGORIC'.
(Other definitions for categoric that I've seen before include "Unambiguously direct" , "Unqualified" , "Positive" , "Absolute" , "Unambiguously explicit" .)