Loco: meaning, definitions and examples

Used informally and often humorously, especially in American English, to describe someone behaving strangely or erratically.

• He went totally loco at the party last night

Common and casual term to describe someone or something as very strange, out of control, or surprising, can be both positive and negative.

• That was a crazy idea, but it worked! // She's crazy about hiking

Used more formally or seriously to describe extreme mental disorder or extreme levels of something. Can have a negative or alarming connotation.

• The workload this week is insane
• // His behavior seemed completely insane

Used commonly in British English to describe someone behaving irrationally or foolishly. Can also mean extremely enthusiastic about something. In American English, it more often means angry.

• That idea is mad; it will never work
• // He's mad about football

Used as an informal and less technical term for a locomotive, often in casual conversations among train enthusiasts.

• I spotted a vintage loco on that abandoned track

A formal and technical term typically used in professional settings or detailed discussions about trains. Refers specifically to the powered rail vehicle that pulls trains.

• The new locomotive model is much more fuel-efficient than the previous one

Commonly used when talking about the mechanical device that moves the train. It can also refer to the central part of a train that provides the power.

• The engine of the train is having some mechanical issues

Used to refer to the entire rail vehicle including the locomotive and all the attached cars. Common in everyday conversation and general discussions about railway travel.

• I take the train to work every day