Mammoth Uncensored Word List:
141 words ending with is, 13 letters long

actinomycosis aerosinusitis amniocentesis antiarthritis antibourgeois apocatastasis arachnoiditis aspergillosis astereognosis atherogenesis autocatalysis bacteriolysis barosinusitis bartonellosis bioprosthesis blastogenesis blastomycosis bronchiolitis capsulorhexis caravansarais caravanserais chiquichiquis cholecystitis chromatolysis coenaesthesis cordocentesis cryptanalysis culdocentesis cyclodialysis cysticercosis cytodiagnosis dynamogenesis elephantiasis embryogenesis endometriosis endosymbiosis enterocolitis epanadiplosis epeirogenesis epicondylitis epidermolysis frontogenesis gametogenesis gastroparesis gastroschisis haemodialysis helminthiasis hematogenesis hematopoiesis heterogenesis heterozygosis histiocytosis homomorphosis hydrarthrosis hyperhidrosis hyperhydrosis hypersarcosis hypnoanalysis immunogenesis iontophoresis labyrinthitis laryngostasis leishmaniasis leishmaniosis leptospirosis lymphadenitis lymphangeitis lymphangiitis lymphocytosis lymphomatosis lymphopoiesis macroanalysis meibomianitis melanogenesis metamorphosis metasomatosis microanalysis mononucleosis morphogenesis mycoplasmosis mycotoxicosis myelofibrosis narcoanalysis narcohypnosis nephrogenesis odontogenesis onomatopoesis onychomycosis organogenesis osteofibrosis osteomyelitis osteonecrosis osteopetrosis overdiagnosis paleotsunamis parapsoriasis parapsychosis parasymbiosis parasynthesis perigastritis perihepatitis perinephritis periodontitis perityphlitis phleborrhexis photophoresis pneumatolysis poliomyelitis polyarteritis polysynthesis postbourgeois presbyacousis psychogenesis psychokinesis pyelocystitis quadriparesis rickettsiosis salmonellosis schizogenesis serodiagnosis speleogenesis spherocytosis spirochetosis spondylolysis subscapularis synchondrosis synecphonesis tachyphylaxis taphrogenesis tenosynovitis tenovaginitis teratogenesis thermogenesis thoracentesis toxoplasmosis tumorigenesis underemphasis venosclerosis visceroptosis xanthomatosis xenodiagnosis