1 syllable:
-cule, b-school, beule, boole, bouille, boule, boulle, bruehl, brule, buehl, buel, buhl, choule, cool, coole, crool, cruel, deuil, dhool, dhule, doole, dreul, drool, dual, duell, dule, fool, frioul, fuel, ghoul, goole, grool, gueule, hoole, huile, j-school, jewel, joule, juel, jule, keule, khul', kool, kreul, luelle, muehl, muelle, mule, noule, pool, poole, poul, poule, reul, reule, rhule, roule, rrdtool, ruel, rule, schuele, schule, scool, scrool, shmuel, shool, shoul, shule, skool, smule, spool, sproule, sproull, spruell, spruiell, spruill, spule, stool, thule, tooele, tool, toole, truel, tuel, tuell, tuille, tuyle, who'll, yeule, you'll, youll, yuill, yuille, yule, zeuhl

2 syllables:
abdul, adule, air-cool, aktuell, alcool, ampoule, arghool, babool, babul, baiul, baoule, barbule, barstool, bascule, befool, blackpool, blastule, bloemkool, board rule, bulbule, cagoule, campstool, capul, car-pool, carpool, cerule, cesspool, chacmool, chevreul, chondrule, ciboule, clausule, claypool, claypoole, close-stool, corcule, corneule, creepschool, cryptool, curule, dame-school, damfool, deadpool, deepcool, deschool, dobule, drogoul, dromgoole, dzhambul, edge tool, ethtool, ethule, faldstool, fanduel, ferrule, ferule, festool, feuille, fistule, floccule, floscule, footstool, foot rule, freedstool, frithstool, g.soul, gag rule, george boole, girlpool, girlschool, glenpool, gribouille, ground rule, guayule, gurule, gwenpool, hand tool, hangeul, heeltool, high-school, highschool, home-rule, home-school, homeschool, home rule, hyrule, infule, insoul, jambool, jambul, kaboul, kagoul, kagoule, kurnool, lawn tool, laycool, lemuel, les claypool, lobule, locule, lovefool, lucule, macule, makhoul, maqbool, mccool, medjool, millijoule, misrule, nabeul, nepool, nucule, o'toole, old-school, omtool, oscule, outfool, outschool, pecul, perule, pethuel, pilule, piquepoul, pistool, plantule, playschool, playskool, plumb rule, pre-school, precool, preschool, pustule, rahul, rantoul, raoul, raul, realschule, recule, retool, rookstool, ruhul, saccule, sandeul, saoul, self-rule, sertule, sesspool, slide rule, spherule, sporule, steenkool, stepstool, step stool, teurgoule, texpool, that you'll, tidepool, tilleul, tim pool, toadstool, tomfool, top-tool, traboule, uncool, unfool, unspool, utsul, valvule, vanpool, vipul, vocule, welshpool, whirlpool, zebrule

3 syllables:
aedicule, after-school, afterschool, agrifuel, amuse-gueule, amygdule, april fool, arbuscule, as-30l, berufsschule, bishop-stool, boerenkool, canicule, caracul, caroncule, chamisul, closestool, coronule, corpuscule, crepuscule, cutting tool, cuttystool, cutty stool, cysticule, digitule, dindigul, ducking-stool, ducking stool, edicule, entitule, exajoule, exiftool, farigoule, fascicule, fenestrule, follicule, gameduell, garden tool, genepool, glomerule, golden rule, graticule, grembiule, groupuscule, hartlepool, hearsay rule, hierodule, intercool, interschool, intitule, ipsambul, istanbul, kab-500l, karakul, karnivool, kilojoule, labor pool, languagetool, lenticule, linalool, liverpool, lodicule, machine tool, machinule, majuscule, megajoule, metarule, milking stool, mille-feuille, minischool, minuscule, molecule, monocule, monticule, motorpool, motor pool, multi-tool, multitool, music stool, nanojoule, neekolul, numbers pool, opercule, opuscule, out-of-school, overrule, parannoul, pedascule, pedicule, pellicule, petajoule, picojoule, planetule, plastidule, poiseuille, pontypool, power tool, propagule, public-school, radebeul, radicule, ramuscule, reticule, ridicule, shaping tool, silicule, snipping tool, somnambule, spinnerule, supercool, swimming-pool, swimming pool, tinkertool, tire tool, ulcuscule, ullapool, unbefool, undercool, vanderpool, vanterpool, vestibule, wading pool, warrnambool, work-to-rule, working rule, wurbagool

4 syllables:
animalcule, annette o'toole, audiotool, bellefeuille, canalicule, carpenter's rule, chevrefeuille, christopher poole, disseminule, endoplastule, entrenching tool, gram-molecule, gram molecule, hemispherule, intellektuell, kab-1500l, linguistic rule, lord of misrule, millefeuille, nonzero-rule, peter o'toole, petiolule, piano stool, poeticule, portefeuille, quatrefeuille, semifloscule, tokyo ghoul

5 syllables:
anonymuncule, apostolopoul, best evidence rule, biomolecule, conciliabule, crazysexycool, dipole molecule, grammatical rule, macromolecule, majority rule, protein molecule, supermolecule, supramolecule

6 syllables:
cyril abiteboul, exclusionary rule

7 syllables:
olympic-size swimming pool

9 syllables:
korea under japanese rule