2 Syllables: SU
breakfast, checklist, deadliest, dexterous, extras, fetish, headless, lettuce, necklace, nexus, plexus, readiest, reckless, reddish, redness, sections, Texas, wreckage
3 Syllables: SUU
3 Syllables: USU
affections, affective, Alexis, collections, collective, complexions, conceptions, connections, connective, connexions, corrections, corrective, correctness, deceptions, deceptive, defective, detective, directions, directive, directness, elections, elective, exceptions, infections, infectious, inflections, injections, inspections, invective, objections, objective, perceptions, perceptive, perfections, perspective, projections, prospective, prospectus, protections, protective, receptions, receptive, reflections, reflective, respective, selections, selective, subjective
4 Syllables: UUSU
imperfections, ineffective, insurrections, intersections, introspective, irrespective, misconceptions, preconceptions, predilections, recollections, retrospective
Found 78 words across 4 groupings. Skipped 6 excess words of a similar stem.