loco

1 of 4

adverb or adjective

lo·​co ˈlō-(ˌ)kō How to pronounce loco (audio)
: in the register as written
used as a direction in music

loco

2 of 4

noun

plural locos or locoes
: 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

3 of 4

verb

locoed; locoing; locos

transitive verb

1
: to poison with locoweed
2
: to make frenzied

loco

4 of 4

adjective

slang
: mentally disordered : frenzied

Examples of loco in a Sentence

Verb years of living alone had clearly locoed the old rancher Adjective The crowd went loco when she walked out on the stage. He's not just weird, he's positively loco.
Recent Examples on the Web
These examples are automatically compiled from online sources to illustrate current usage. Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Adverb or adjective
Breakfast hits include mahi eggs Benedict and loco moco, a hearty Hawaiian staple of eggs, a beef patty, and steamed rice smothered in a rich gravy. Jen Murphy, Outside Online, 29 Dec. 2022
Noun
The combinations are spectacular: think abalone-like locos with peas and a touch of grapefruit foam paired with a green tea from Sichuan, China. Nicholas Gill, TIME, 25 July 2024 For now, visitors can do our small part by getting our hands dirty, then savoring loco moco whipped up with aloha. Michele Bigley, TIME, 25 July 2024
Adjective
Real investors survey the landscape and look for signs of a market gone loco. Andy Kessler, WSJ, 2 July 2017 As one of my colleagues said, this was straight loco. Ryu Spaeth, New Republic, 28 July 2017 See all Example Sentences for loco 

Word History

Etymology

Adverb or adjective

Italian dialect, there, from Latin in loco in the place

Noun

Mexican Spanish, from Spanish, crazy

Adjective

Spanish

First Known Use

Adverb Or Adjective

1786, in the meaning defined above

Noun

1844, in the meaning defined above

Verb

1884, in the meaning defined at sense 1

Adjective

1852, in the meaning defined above

Time Traveler
The first known use of loco was in 1786

Dictionary Entries Near loco

Cite this Entry

“Loco.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/loco. Accessed 8 Nov. 2024.

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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