2 Syllables: SU
biggest, bigots, billets, biscuits, bishops, Christmas, citrus, dearest, digits, dimness, fittest, frigates, grimace, hillocks, image, inches, India's, Indus, interests, isthmus, limits, lineage, linkage, listless, minutes, minutest, mistress, nearest, Nicholas, nitrous, Philips, pickets, Plymouth, princes, quibus, richest, rivets, simplest, sinless, sinuous, spinach, thickets, tickets, vicious, viscous
3 Syllables: USU
ambitious, archbishops, assiduous, auspicious, bacillus, capricious, delicious, distinctness, elicits, exhibits, factitious, fictitious, inhibits, judicious, malicious, Narcissus, nutritious, officious, Olympus, pernicious, prestigious, prodigious, prohibits, propitious, religious, seditious, severest, sincerest, suspicious, utilise
4 Syllables: UUSU
adventitious, avaricious, expeditious, ignominious, injudicious, irreligious, superstitious, surreptitious, unpropitious, unsuspicious
Found 85 words across 3 groupings. Skipped 3 excess words of a similar stem.