What does wacko mean?
Wacko is an informal word for something or someone that is crazy, eccentric, or unusually unconventional. As an adjective, it commonly describes an idea, plan, outfit, or situation that seems strange or wildly exaggerated: “That is the most wacko invention I have ever seen.” As a noun, it refers to a crazy or eccentric person, although this use can sound insulting rather than playful. The adverb form occurs in expressions such as “go wacko,” meaning to behave in a crazily excited or uninhibited way. Although wacky is the more established spelling, wacko is also common, particularly in American informal speech and comic contexts. It has a lively, exaggerated tone, so it is usually better suited to conversation, humor, and creative writing than to formal discussion. The word is especially useful when a speaker wants to portray something not merely odd, but dramatically unconventional or comically excessive.
Informally, eccentric, crazy, or unconventional, often in a humorous or exaggerated way.
"The committee proposed a wacko scheme involving invisible mailboxes."
Often used comically to emphasize how unusual or extreme something is.
Informally, a crazy or eccentric person.
"At first everyone thought the new neighbor was a wacko."
Can be playful, but may be derogatory when used to describe someone seriously.
In a crazy, eccentric, or wildly unconventional manner.
"The children started wacko as soon as the music began."
Most often encountered in the informal expression 'go wacko.'
The plural is used when referring to multiple eccentric or crazy people.
"The two wackoes arrived with a map covered in imaginary landmarks."
Wacko is the playful, often more exaggerated spelling of wacky, making it ideal for comic exaggeration and informal storytelling.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does wacko come from?
Wacko developed as an informal spelling variant of wacky, an earlier word meaning “eccentric” or “crazy.” The deeper origin of wacky is uncertain, so it is safest to treat wacko and its close variants as playful extensions rather than trace them to a securely known root. The form became associated with comic and exaggerated informal English.
Related word forms
How wacko is actually used
Wacko is informal and mainly North American in use. It is often humorous, but the noun can be derogatory when applied to a person. The expression 'go wacko' means to behave crazily or become wildly excited.
Easily confused with wacko
Wacky and wacko are closely related informal spellings, but wacko is often used for something more extreme or comically exaggerated.