Mammoth Uncensored Word List:
90 words ending with sm, 15 letters long

annihilationism anthropopathism anticlericalism anticolonialism antimaterialism antirationalism antiromanticism archeomagnetism assimilationism autodidacticism bacchanalianism bluestockingism brachycephalism brachydactylism confessionalism conservationism constructionism conventionalism conversationism cosmopolitanism departmentalism dermatographism diaheliotropism diaphototropism doctrinarianism ecclesiasticism enantiomorphism entrepreneurism episcopalianism equalitarianism experientialism experimentalism futilitarianism governmentalism heliocentricism hereditarianism hermaphroditism humanitarianism hyperadrenalism hypercatabolism hyperinsulinism hypermetabolism hyperparasitism hyperthyroidism hypopituitarism instrumentalism insurrectionism intellectualism interventionism intransigentism macrometabolism majoritarianism mechanomorphism melodramaticism metropolitanism multilateralism multilingualism neoconservatism nonessentialism nothingarianism oneirocriticism opisthognathism orthochromatism palaeomagnetism parliamentarism photojournalism poikilothermism polysyllabicism preferentialism preformationism presbyterianism presentationism professionalism resurrectionism scaphocephalism semicolonialism solvatochromism stereoisomerism sublapsarianism supernaturalism superorganicism superparasitism superpatriotism supersensualism therianthropism thermoperiodism thromboembolism totalitarianism ubiquitarianism ultraliberalism