2 Syllables: SU
adjunct, ashen, Ashton, aspen, Aston, Athens, bastion, Caspian, chasm, craftsman, draughtsman, fashion, fasten, fathom, Gaston, Grafton, jasmine, javelin, Latham, Masson, pageant, passion, ration, saffron, savants, spasm
3 Syllables: USU
assassin, attachment, compassion, detachment, harassment, imagine, impassioned, oldfashioned, potassium, Sebastian
Found 36 words across 2 groupings. Skipped 17 excess words of a similar stem.