2 Syllables: SU
biggest, bigot, billet, biscuit, Bishop, Bridget, Christmas, citrus, dearest, digit, drifted, fittest, frigate, frigid, gifted, grimace, hillock, isthmus, lifted, limit, listed, listless, millet, minute, minutest, mistress, nearest, Nicholas, nitrous, Philip, pickets, pivot, quibus, richest, rigid, rivet, shifted, spinach, spirit, syrup, thickets, ticket, twisted, vicious, viscous, vivid, wicket
3 Syllables: USU
ambitious, Archbishop, assiduous, assisted, auspicious, bacillus, capricious, consisted, deliberate, delicious, elicits, exhibits, existed, explicit, factitious, fictitious, illicit, implicit, inhibit, initiates, insisted, judicious, malicious, Narcissus, nutritious, officious, pernicious, prestigious, prodigious, prohibit, propitious, religious, resisted, seditious, severest, sincerest, suspicious, utilise
4 Syllables: UUSU
adventitious, avaricious, expeditious, injudicious, irreligious, superstitious, surreptitious, unpropitious, unsuspicious
Found 94 words across 3 groupings. Skipped 17 excess words of a similar stem.