Or search: fete, mourn, revel, honour, racket, lionize, lionise, wassail, jubilate, solemnise, commemorate
2 Syllables: SU
separate
3 Syllables: SUU
celebrates, decorate, dedicate, delegate, deprecate, desolate, educate, elevate, emanate, emigrate, estimate, generate, hesitate, meditate, penetrate, predicate, segregate, separates, venerate
4 Syllables: USUU
accelerate, commemorate, confederate, degenerate, disseminate, interrogate, investigate, necessitate, perpetuate, regenerate
5 Syllables: UUSUU
overestimate, underestimate

Found 32 words across 4 groupings. Skipped 12 excess words of a similar stem.