Or search: downer, doriden, ataractic, depressant, medication, medicament, glutethimide, tranquilizing, tranquilising, tranquillising
1 Syllable: S
Rep
2 Syllables: SU
beverage, hemorrhage, leverage
3 Syllables: SUU
crevices, decorative, equipage, menaces, narrative, necklaces, negative, prefaces, relative, terraces, threatenings
4 Syllables: USUU
competitive, consecutive, correlative, executive, imperative
5 Syllables: UUSUU
representative

Found 21 words across 5 groupings. Skipped 7 excess words of a similar stem.