Mammoth Uncensored Word List:
109 words ending with on, 5 letters long

aboon acton ammon ancon anion anyon apron argon arson avion axion azlon bacon baron bason baton belon beton bidon bison boron boson cajon canon capon caxon codon cogon colon croon cyton demon devon eikon ergon fanon felon freon futon gazon gipon giron gluon gyron halon heron holon hyson inion ippon jeton jomon jupon kroon lemon logon macon maron mason melon meson moron muton ninon niton nylon odeon onion orlon paeon pelon pheon piton pleon prion psion pylon racon radon rayon recon redon rejon rewon roton salon sayon scion seron seton shoon solon spoon swoon talon tauon taxon tenon tigon timon toyon union unwon urson vison wagon xenon yapon yupon