Mammoth Uncensored Word List:
56 words ending with or, 13 letters long

administrator aerogenerator authenticator chemoreceptor coconspirator conglomerator conglutinator congratulator counterterror dechlorinator deconstructor defibrillator deflocculator depressomotor discriminator disintegrator indoctrinator interbehavior intermediator interpellator lithontriptor microdetector miscalculator monochromator multidetector multiplicator multivibrator noncompetitor noncontractor noncooperator nonlegislator overestimator photodetector photoreceptor plantarflexor postprocessor predestinator prefabricator pretranslator proprioceptor reconciliator reconstructor rehabilitator reinvigorator semiconductor simplificator somnambulator sophisticator subcontractor substantiator supererogator tergiversator transmigrator vasodepressor vasoinhibitor wordprocessor