Or search: tip, acme, peak, crest, spire, summit, tiptop, elevate, steeple, meridian, surmount, elevation, superlative, architecture
2 Syllables: SU
mineral
3 Syllables: SUU
Biblical, clinical, criminal, difficult, digital, integral, liberal, literal, littoral, minimal, miracle, mythical, pitiful, pivotal, principal, principle, syllable, typical, visceral, visible, visual
3 Syllables: USU
peripheral
4 Syllables: SUUU
formidable
4 Syllables: USUU
additional, admissible, conditional, derivable, despicable, divisible, divisional, Episcopal, equivocal, explicable, hospitable, illiberal, invincible, invisible, medicinal, municipal, nutritional, occipital, original, permissible, political, pontifical, provisional, reciprocal, satirical, traditional, transitional, unprincipled, unthinkable
5 Syllables: UUSUU
aboriginal, inadmissible, individual, inexplicable, inhospitable, irresistible, monosyllables, unconditional, unequivocal

Found 62 words across 6 groupings. Skipped 11 excess words of a similar stem.