loco

American  

[loh-koh] / ˈloʊ koʊ /

noun

plural

locos

1. locoweed.

2. Slang. an insane person; maniac.

3. Veterinary Pathology. locoism.

---

verb (used with object)

locoed, locoing

1. to poison with locoweed.

2. Slang. to cause to be insane or crazy.

adjective

1. Slang. out of one's mind; insane; crazy.

loco ¹ British  

/ ˈləʊkəʊ /

adjective

1. slang insane

2. (of an animal) affected with loco disease

---

noun

1. short for locoweed

verb

1. to poison with locoweed

2. slang to make insane

loco ² British  

/ ˈləʊkəʊ /

noun

1. informal short for locomotive

---

loco ³ British  

/ ˈləʊkəʊ /

adjective

1. denoting a price for goods, esp goods to be exported, that are in a place specified or known, the buyer being responsible for all transport charges from that place

   loco Bristol

   a loco price

---

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

It has so far published one game, point-and-click adventure Loco Motive.

From BBC • Apr. 16, 2026

El Pollo Loco traces its history to the 1970s in Guasave, Sinaloa, Mexico, where it was started by shoe salesman Pancho Ochoa using his family’s citrus-marinated chicken recipe.

From Los Angeles Times • Mar. 13, 2026

And, Adam says, it's about doing what you can to give your game the best chance - Loco Motive's big marketing push was launched close to release to keep the momentum going.

From BBC • Nov. 29, 2024

Blxst revealed that the last meal he ate in his car was on the drive back from Coachella: a burrito from Loco Burrito in Moreno Valley.

From Los Angeles Times • Apr. 18, 2024

It doesn't even have to be your real name—like Loco who lives on Woodbine Street.

From "Brown Girl Dreaming" by Jacqueline Woodson