3 Syllables: SUU
4 Syllables: USUU
acceptable, conjectural, delectable, detectable, electoral, electrical, exceptional, execrable, heretical, impeccable, impregnable, incredible, inflexible, perceptible, perceptual, poetical, receptacle, regrettable, respectable, susceptible, symmetrical
5 Syllables: UUSUU
alphabetical, antithetical, architectural, arithmetical, asymmetrical, dialectical, directional, geometrical, hypothetical, imperceptible, theoretical, unacceptable, unforgettable
Found 44 words across 3 groupings. Skipped 2 excess words of a similar stem.