Mammoth Uncensored Word List:
93 words ending with us, 15 letters long

achlorophyllous amaryllidaceous andromonoecious anthropophagous antituberculous asclepiadaceous bacteriophagous basidiomycetous brachycephalous brachydactylous caprifoliaceous carpometacarpus chenopodiaceous chromatophorous circumambagious circumforaneous coinstantaneous collenchymatous contemporaneous convolvulaceous cytomegalovirus cytomegolovirus deuteranomalous disadvantageous echinodermatous edriophthalmous eleutherococcus enantiomorphous enchondromatous epitheliomatous excrementitious extramembranous fasciocutaneous gasteromycetous gnathostomatous hamamelidaceous heterodactylous homochlamydeous hydrosulphurous hyperfastidious hypophosphorous intermembranous lissencephalous margaritiferous megalocephalous menispermaceous mesaticephalous metapneumovirus monochlamydeous mucosanguineous myristicivorous nonadvantageous nonasynchronous nonglaucomatous nonmucilaginous nonsimultaneous nonsubconscious odontorhynchous odontostomatous opisthognathous ornithodelphous ornithorhynchus overincredulous parthenocarpous passifloraceous pergamentaceous pithecanthropus plagiostomatous plantaginaceous plumbaginaceous poikilothermous prosenchymatous protospatharius pseudoreligious pulchritudinous radiophosphorus recrementitious sarcenchymatous sarraceniaceous scaphocephalous sclerodermatous streptobacillus strombuliferous stylopharyngeus tarsometatarsus tentaculiferous ultrafastidious unconscientious unconsentaneous unfossiliferous unselfconscious vicissitudinous zygophyllaceous