2 syllables:
aero, aero-, arrow, barrow, bero, berro, cerro, cheiro, cheiro-, chero, clairo, clero, cuero, darrow, derro, derrow, eroh, faeroe, faro, fero, ferro, ferro-, fuero, garo, garrow, gero, gero-, gerow, guero, guerro, herro, lerro, marrow, mero, meroe, merow, merowe, merrow, narrow, pairo, pharao, pharaoh, pharoah, phero, ptero, quero, serro, shero, sherrow, sparrow, spero, sphaero, sphero, stero, taro, terro, thero, varo, vero

3 syllables:
acero, aguero, albero, alero, alghero, alvero, amero, antero, antero-, armero, aspero, austero, aveiro, barbero, barquero, barreiro, bolero, bone marrow, borrero, botero, bracero, brasero, bucchero, cabrero, cajero, caldero, calero, camaro, camero, cantero, carneiro, carnero, carreiro, carrero, cartero, casero, cepero, cordeiro, cordero, course hero, crucero, cruzeiro, dattero, delnero, dinero, dinheiro, dondero, enero, entero, estero, esthero, exxaro, favero, febrero, ferreiro, ferrero, fichero, field sparrow, fisherrow, galero, gambero, gastero, gippsaero, granero, granjero, guerreiro, guerrero, handbarrow, hedge sparrow, herero, herrero, house sparrow, hystero, hystero-, ibero, ibero-, ictero, impero, intero, iraero, janiero, jezero, juazeiro, juicero, korero, latero, latero-, leggero, libero, ligero, llanero, lonero, lonkero, loureiro, lucero, madero, marero, marrero, maspero, melero, minero, mistero, monero, monteiro, montero, nispero, nonhero, nonzero, numero, oneiro, otero, overo, pajero, palmero, pandeiro, passero, peguero, pepero, pierce-arrow, piffero, pineiro, pinero, pinheiro, polperro, pombero, portero, postero, potrero, primero, prospero, protero, protero-, puchero, puntero, quintero, ranchero, red sparrow, rezero, ribeiro, rivero, romero, ropero, rosero, ruggero, salero, salgueiro, salguero, santero, sendero, sidero, silguero, sincero, soltero, sombrero, somero, song sparrow, straight-arrow, suadero, supaero, suwarrow, swamp sparrow, tablero, tenero, tercero, torero, transaero, trasero, tree sparrow, true sparrow, tubero, uparrow, valero, vaquero, velero, vimeiro, vivero, wheelbarrow, zanjero, zotero, zucchero, zurcaroh

4 syllables:
aguacero, agujero, alfarero, alfiero, anti-hero, archivero, asadero, astillero, bandolero, brasileiro, brigadeiro, burladero, caballero, cafiero, calimero, calogero, camarero, campanero, candelero, canserbero, cape passero, carbonero, carnicero, carpintero, cavalero, cavallero, cenicero, chipping sparrow, ciminero, cimitero, cocinero, colmenero, comanchero, companero, curandero, delfavero, diablero, english sparrow, escudero, espartero, extranjero, fevereiro, forastero, franco nero, ganadero, giant taro, golden yarrow, guerrillero, habanero, heredero, hormiguero, ingeniero, jardinero, java sparrow, locicero, marinero, mazzaferro, mensajero, mescalero, messaggero, messeghero, mogavero, monastero, mugavero, nakasero, new world sparrow, novillero, olivero, panadero, paradero, paterero, patintero, pederero, peluquero, peterero, pistolero, pseudo-nero, raniero, recupero, rent-a-hero, ronan farrow, saladero, salinero, straight and narrow, straniero, taliaferro, tapadero, terutero, tinajero, tyler herro, varadero, verdadero, verdulero, vesper sparrow, zapatero, zifferero

5 syllables:
atascadero, azucarero, banderillero, botafumeiro, carabinero, condottiero, eddie guerrero, elicottero, embarcadero, encomendero, financiero, frigorifero, george a. romero, invernadero, lillibullero, vegetable marrow, velocifero, yoel romero

6 syllables:
alfonso ribeiro, ana peleteiro, melissa fumero

7 syllables:
california romero, mitsubishi pajero

8 syllables:
italian vegetable marrow, rafael caro quintero, the rising of the shield hero

2 syllables:
euro, sorrow, biro, serow, harrow, hero, beroe, yarrow, bureau, gyro, claro, miro, borrow, borough, farrow, zero, spiro, morrow, cairo, burro, burrow, furrow, pirro, thorough

3 syllables:
tomorrow, broad arrow, sapporo, saguaro, guacharo, straight arrow, disk harrow, deniro, disc harrow, ferraro, janeiro, mindoro, restharrow, sahuaro, shapiro, sokoro

4 syllables:
credit bureau, autogiro, service bureau, weather bureau, autogyro, antihero, rotten borough, pocket borough, bow and arrow, aleph-zero, bodo-garo, census bureau, poroporo, rabbit burrow

5 syllables:
chiaroscuro, kilimanjaro, absolute zero

6 syllables:
rio de janeiro, mount kilimanjaro