Or search: resistant, impervious, impermeable
3 Syllables: SUU
amiable, cervical, enviable, malleable, permeable, pitiable, purposeful, terminal, variable, versatile, vertebral, virginal, workable, worshipful
3 Syllables: UUS
agreeable, foreseeable
4 Syllables: USUU
convertible, discernible, impersonal, invariable, observable, reversible, transferable, unenviable, unworkable
4 Syllables: UUUS
disagreeable
5 Syllables: UUSUU
interpersonal, irremediable, irreversible

Found 29 words across 5 groupings. Skipped 1 excess word of a similar stem.