loco

1 of 2

noun

plural locos or locoes
Synonyms of loconext
: any of several leguminous plants (genera Astragalus and Oxytropis) of western North America that contain a toxin that causes locoism especially in livestock when ingested in large quantities : locoweed

loco

2 of 2

verb

locoed; locoing; locos

transitive verb

1
: to poison with locoweed
2
: to make frenzied

Examples of loco in a Sentence

Verb years of living alone had clearly locoed the old rancher
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Noun
Guevara hit a loco dive off the ladder. Ryan Gaydos, FOXNews.com, 17 May 2026 The locos pull right into the vast expanse of what was once the Zetland Hotel but has now transformed into some seriously spacious apartments. Rob Crossan, Condé Nast Traveler, 13 May 2026 Poke, loco moco, kalua pig and huli huli chicken are all Hawaiian classics, but ignore the Puka Dog at your gustatory peril. Catherine Garcia, TheWeek, 27 Mar. 2026 Specialties here are bibimbap, loco moco and Korean Benedict with shortribs and kimchi fried rice. Laura Ness, Mercury News, 8 Feb. 2026 See All Example Sentences for loco

Word History

Etymology

Noun

Mexican Spanish, from Spanish, crazy

First Known Use

Noun

1844, in the meaning defined above

Verb

1884, in the meaning defined at sense 1

Time Traveler
The first known use of loco was in 1844

Browse Nearby Words

Cite this Entry

“Loco.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/loco. Accessed 9 Jun. 2026.

Kids Definition

loco

adjective
lo·​co
ˈlō-kō
slang
: mentally disordered

Medical Definition

loco

1 of 2 noun
lo·​co ˈlō-(ˌ)kō How to pronounce loco (audio)
plural locos or locoes
: any of several plants (genera Astragalus and Oxytropis) of western North America that contain a toxin that causes locoism in livestock when ingested in large quantities : locoweed

loco

2 of 2 transitive verb
: to poison with locoweed
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