Mammoth Uncensored Word List:
209 words ending with um, 8 letters long

abomasum achenium aciculum aconitum actinium addendum aecidium aerobium ageratum alburnum allodium alluvium aluminum ammonium anestrum apterium aquarium argentum ascidium aspidium atheneum basidium bdellium biennium blackgum bothrium brachium caladium canticum capsicum cardamum cementum cerebrum cervicum checksum chromium ciborium cingulum coagulum cocoplum coliseum conarium conidium corallum coremium coronium corundum crotalum cyathium cymatium delirium delubrum didymium diestrum diluvium disodium domatium dominium duodenum electrum emporium encomium eryngium eulogium europium exemplum exordium extremum factotum francium frenulum furculum fusarium galbanum geranium glucinum gonidium graphium guaiacum guaiocum gynecium helenium humstrum hymenium hypogeum illuvium imperium indicium indusium ingenium inoculum isodomum labdanum labellum laburnum laudanum linoleum lixivium lomentum lutecium lutetium macallum masurium meconium mezereum mocuddum momentum monstrum motorium mutandum mycelium nebulium ngultrum nobelium notandum olibanum ommateum oncidium onychium oogonium opsonium ordalium origanum ossarium overswum paspalum patagium peculium pendulum peponium peridium perineum pessimum philtrum phormium placitum plastrum platinum plectrum polonium poppadum pronotum proprium psyllium pudendum pullorum pulpitum puparium puppodum pygidium pyxidium ramentum ranarium refugium residuum rosarium rubidium sacellum saeculum samarium scalprum scandium schellum scholium scybalum secundum sedilium selenium silicium silphium simulium solarium solatium soredium spectrum speculum sphagnum spiculum splenium striatum sudarium syconium syzygium tantalum teetotum tenendum testatum thallium tillicum timpanum titanium tomentum trillium triticum tympanum ununbium vanadium variorum vasculum velarium venidium veratrum vexillum viaticum viburnum videndum vinculum vivarium zooecium