adjective
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slang insane
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(of an animal) affected with loco disease
noun
verb
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to poison with locoweed
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slang to make insane
noun
adjective
Other Word Forms
Noun Inflected Forms
Etymology
Origin of loco
1835–45, < Spanish: insane
Explanation
If someone calls you loco, it means they think you're nutty or eccentric. Your friends will think your dog is completely loco if she spends hours every day chasing her own tail. You can use the slang term loco when you're commenting on the craziness or irrationality of a person or situation. You might say, for example: "This meeting is totally loco — everyone's talking at the same time!" Loco comes from American English, which borrowed it from the Spanish loco, "insane." Its roots are uncertain, but it may stem from the Arabic lauqa, "fool."
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Davidson analyst Matt Curtis, in a note on Monday, said El Pollo Loco was selling more orders with three to four pieces, as opposed to orders with only two.
From MarketWatch • Jun. 16, 2026
It has so far published one game, point-and-click adventure Loco Motive.
From BBC • Apr. 16, 2026
El Pollo Loco may be just the right combination of price and differentiation from fast-food burgers at a time when consumers are looking to save.
From Los Angeles Times • Mar. 13, 2026
Southern California’s El Pollo Loco, known for its flame-grilled chicken, is eyeing further national expansion after announcing surprisingly strong results for last year.
From Los Angeles Times • Mar. 13, 2026
It doesn't even have to be your real name—like Loco who lives on Woodbine Street.
From "Brown Girl Dreaming" by Jacqueline Woodson
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
