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2 Syllables: SU
foreigner
3 Syllables: SUU
auditors, commoner, gossamer, monitor, officer, oftener, Oliver, Waterford, waterworks
4 Syllables: SUUU
kilometers
4 Syllables: USUU
astrologer, astronomer, biographer, geographer, idolaters, philosopher, photographer, thermometer
4 Syllables: UUSU
kilometres

Found 20 words across 5 groupings. Skipped 12 excess words of a similar stem.