WordNet (r) 3.0 (2006):

pesticide
    n 1: a chemical used to kill pests (as rodents or insects)

Moby Thesaurus II by Grady Ward, 1.0:

90 Moby Thesaurus words for "pesticide":
   Cain, aborticide, acaricide, anthelmintic, antibiotic, antiseptic,
   apache, assassin, assassinator, bactericide, bloodletter,
   bloodshedder, bravo, bug bomb, burker, butcher, button man,
   cannibal, carbamate insecticide, chemosterilant,
   chlorinated hydrocarbon insecticide, contact poison, cutthroat,
   defoliant, desperado, disinfectant, eradicant, eradicator,
   executioner, exterminator, fratricide, fumigant, fungicide,
   garroter, genocide, germicide, gorilla, gun, gunman, gunsel,
   hatchet man, head-hunter, herbicide, hit man, homicidal maniac,
   homicide, infanticide, insect powder, insecticide, killer,
   man-eater, man-killer, manslayer, massacrer, matador, matricide,
   microbicide, miticide, murderer, organic chlorine,
   organic phosphate insecticide, parricide, patricide, poison,
   poisoner, rat poison, regicide, roach paste, roach powder,
   rodenticide, slaughterer, slayer, sororicide, stomach poison,
   strangler, suicide, systemic, systemic insecticide, thug, torpedo,
   toxic, toxicant, toxin, trigger man, uxoricide, venin, venom,
   vermicide, virus, weed killer