Or search: abstractionist
2 Syllables: SU
desperate, Frederick, separate
3 Syllables: SUU
Arabic, Baroness, Benedict, benefice, benefit, derelict, Federalists, feminist, heretic, Methodist, Nemesis, prejudice, rhetoric, sensitive, separates, specialist, tentative, terrorist, therapist
4 Syllables: USUU
commemorative, contemplative, insensitive, unprejudiced
5 Syllables: UUSUU
argumentative, representative

Found 28 words across 4 groupings. Skipped 4 excess words of a similar stem.