Canoeing recklessly across river shows unawareness (9)
I believe the answer is:
ignorance
'unawareness' is the definition.
(thesaurus)
'canoeing recklessly across river' is the wordplay.
'recklessly' indicates anagramming the letters.
'across' is an insertion indicator.
'river' becomes 'r'.
'canoeing' is an anagram of 'ignoance'.
'ignoance' placed around 'r' is 'IGNORANCE'.
'shows' is the link.
(Other definitions for ignorance that I've seen before include "Nescience" , "being uninformed" , "Possibly bliss?" , "'Where . . . . . . . . . is bliss, 'tis folly to be wise'" , "Not knowing" .)