Or search: shaky, uneasy, unsafe, parlous, insecure, perilous, unstable
2 Syllables: SU
areas, barest, carriage, chariots, deadliest, Eliot's, fairness, ferrous, heaviest, heiress, merest, rarest, readiest, sheriff, tariff, terrace, terras, various
3 Syllables: SUU
penniless, readiness
3 Syllables: USU
awareness, calcareous, embarrass, gregarious, hilarious, miscarriage, nefarious, unfairness, vicarious
4 Syllables: UUSU
multifarious

Found 30 words across 4 groupings. Skipped 5 excess words of a similar stem.