[ pis-tl-air-oh; Spanish pees-taw-le-raw ]
/ ˌpɪs tlˈɛər oʊ; Spanish ˌpis tɔˈlɛ rɔ /

noun, plural pis·to·le·ros [pis-tl-air-ohz; Spanish pees-taw-le-raws] /ˌpɪs tlˈɛər oʊz; Spanish ˌpis tɔˈlɛ rɔs/. (esp. in Mexico and Central America)

a member of an armed band of roving mounted bandits.
a gunman or hired killer.

Origin of pistolero

1935–40; < Spanish, equivalent to pistol(a) pistol + -ero < Latin -ārius -ary
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019