nonconducting

from WordNet (r) 3.0 (2006)

nonconducting
    adj 1: not able to conduct heat or electricity or sound [syn:
           {nonconductive}, {nonconducting}, {non-conducting}] [ant:
           {conductive}]

from The Collaborative International Dictionary of English v.0.48

Nonconducting \Non`con*duct"ing\, a.
   Not conducting; nonconductive; not transmitting a fluid or
   force; -- used especially of electric current; thus, in
   electricity, wax is a nonconducting substance.
   [1913 Webster +PJC]