Or search: pit, sac, sack, decay, lumen, orbit, pouch, sinus, cavum, cecum, celom, divot, fossa, armpit, hollow
3 Syllables: SUU
classically, drastically, graphically, gravity, magically, placidly, tacitly, tragically
4 Syllables: USUU
capacities, capacity, fantastically, humanities, localities, rapacity, sagacity, sarcastically, tenacity, veracity, vivacity
4 Syllables: UUSU
analyses
5 Syllables: UUSUU
geographically, nationalities, personalities, principalities
6 Syllables: UUUSUU
enthusiastically, municipalities

Found 26 words across 5 groupings.