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

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

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

5 syllables:
absolute zero, chiaroscuro, kilimanjaro

6 syllables:
henry david thoreau, mount kilimanjaro, rio de janeiro