1 syllable:
bloom's, blooms, boom's, booms, brooms, coombes, coombs, coomes, crooms, dooms, flumes, fumes, glooms, glumes, groomes, grooms, humes, khoums, khums, looms, lumes, neumes, neums, plumes, rheums, rhumbs, room's, rooms, shrooms, spumes, tombs, toombs, tooms, wombs, zooms

2 syllables:
agrumes, assumes, backrooms, ballrooms, barrooms, bathrooms, bazooms, bedrooms, boardrooms, bridegroom's, bridegrooms, broadlooms, chatrooms, checkrooms, classrooms, cloakrooms, clubrooms, consumes, costumes, courtrooms, darkrooms, entombs, exhumes, greenrooms, guardrooms, handlooms, heirlooms, homerooms, illumes, inhumes, legumes, lunchrooms, mailrooms, maktoums, newsroom's, newsrooms, parfums, perfumes, playrooms, poolrooms, presumes, relumes, restrooms, resumes, salesrooms, schoolrooms, showrooms, sickrooms, simooms, staterooms, stockrooms, storerooms, strongrooms, subsumes, sunrooms, tearooms, wardrooms, washrooms, workrooms

3 syllables:
anterooms, exhaust fumes, foredooms, livingrooms, oyo rooms, reassumes, salerooms

4 syllables:
openclassrooms