Uncertain rules I tore in pieces (10)
I believe the answer is:
irresolute
'uncertain' is the definition.
(I've seen this before)
'rules i tore in pieces' is the wordplay.
'in pieces' indicates anagramming the letters.
'rules'+'i'+'tore'='rulesitore'
'rulesitore' is an anagram of 'IRRESOLUTE'.
(Other definitions for irresolute that I've seen before include "Hesitating" , "Indecisive" , "lacking clear purpose" , "Hesitant, uncertain" .)