Or search: smell, noesis, insight, sensing, tasting, smelling, esthesis, beholding, cognition, constancy, detection, listening, sensation, aesthesis, lipreading
2 Syllables: SU
beckon, Bedlam, Breton, deaden, Edmond, Edmund, Edwin, Epsom, extant, leaden, Leben, pregnant, reckon, rectum, reddened, requiem, second, section, segment, septum, sexton, spectrum, threaten, veteran, weapon
3 Syllables: SUU
dissection
3 Syllables: USU
acceptance, affection, collection, complexion, conception, connection, connexion, convection, correction, deception, defection, deflection, dejection, detection, direction, ejection, election, erection, exception, expectant, inception, infection, inflection, injection, inspection, investment, objection, perceptions, perfection, projection, protection, reception, reflection, reflexion, rejection, selection, subjection
4 Syllables: UUSU
circumspection, disaffection, imperfection, insurrection, interregnum, intersection, introspection, Mahometan, misconception, preconceptions, predilection, recollection, reelection, resurrection

Found 77 words across 4 groupings. Skipped 40 excess words of a similar stem.