Mammoth Uncensored Word List:
42 words ending with r, 16 letters long

abdominoanterior atrioventricular autolithographer autoradiographer barocyclonometer benzyloxycamphor biostratigrapher crystallographer extracorpuscular extraventricular greatgrandfather greatgrandmother hepatolenticular intellectualizer interventricular intracanalicular intraventricular lighthousekeeper microcalorimeter micromanipulator microseismometer neurotransmitter nonfibrolamellar numismatographer pachycephalosaur photographometer photointerpreter photopolarimeter photosynthesiser photosynthesizer prediscriminator psychobiographer radiobroadcaster radiotelegrapher sphygmomanometer sternoclavicular superspectacular supraventricular transilluminator tubuloglomerular ultrasonographer videoconferencer