Unaware of ranting wildly about nothing (8)
I believe the answer is:
ignorant
'unaware of' is the definition.
(to be ignorant of something is to be unaware of it)
'ranting wildly about nothing' is the wordplay.
'wildly' indicates an anagram.
'about' is an insertion indicator.
'nothing' becomes 'o' (O resembles 0).
'ranting' anagrammed gives 'ignrant'.
'ignrant' placed around 'o' is 'IGNORANT'.
(Other definitions for ignorant that I've seen before include "Rude or knowing very little" , "ill-advised" , "Uneducated" , "Empty-headed" , "Lacking in education" .)