Caution — answer is cryptic (8)
I believe the answer is:
'caution' is the definition.
(wariness is a kind of caution)
'answer is cryptic' is the wordplay.
'cryptic' indicates an anagram.
'answeris' with letters rearranged gives 'WARINESS'.
(Other definitions for wariness that I've seen before include "Caution, watchfulnes" , "Circumspection" , "State of caution" .)