resmethrin
noun
res·meth·rin (ˌ)rez-ˈmeth-rin 
-ˈmēth-
: a nonpersistent synthetic insecticide C22H26O3 that is a derivative of pyrethrin and is used in aerosols
Word History
Etymology
res- (probably transposed from ester) + -methrin, blend of methyl and -ethrin (as in pyrethrin)
First Known Use
1971, in the meaning defined above