1 of 2


psy·​cho ˈsī-(ˌ)kō How to pronounce psycho (audio)
plural psychos
informal + disparaging


2 of 2


informal + disparaging
: of, relating to, or being a person who is mentally or emotionally unsound or unstable especially in a way that results in dangerous or violent behavior

Examples of psycho in a Sentence

Recent Examples on the Web
Texturally, the series is best categorized as a psycho-thriller, but the design of the episodes is never redundant. WIRED, 17 Mar. 2023 Another summer, another hook-wielding psycho killer — and maybe some familiar faces too. Jessica Wang,, 7 Feb. 2023 Melissa Barrera as Sam Carpenter Melissa Barrera 'Scream VI.' | Credit: Philippe Bossé/Paramount Tara's sister Sam has also moved east to keep an eye on her sibling and an eye out for a certain mask-wearing psycho. Clark Collis,, 8 Mar. 2023 How James Dearden’s original script entered development as a sympathetic portrayal of a single woman until studio execs turned it into the story of a villainous, largely unsympathetic psycho. Vulture, 5 Apr. 2022 Yet the bear adds gore and suspense and a soupçon of lurid excitement, the same way that an ax-wielding psycho does. Owen Gleiberman, Variety, 23 Feb. 2023 Here is McCarthy’s God: a deranged psycho who not only tolerates his world’s atrocities but conceives of them in these strange and inhuman terms. Graeme Wood, The Atlantic, 5 Dec. 2022 Gen X icons Courteney Cox, Neve Campbell, and David Arquette teach some Gen Z whippersnappers how to avoid being murdered by a masked psycho in the new trailer for Scream 5. Jon Blistein, Rolling Stone, 12 Oct. 2021 Australian actor Josh Lawson as the psycho Kano steals the movie with enough twisted humor to deserve his own franchise. Mark Kennedy, Star Tribune, 22 Apr. 2021 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'psycho.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History



short for psychopath


short for psychopathic entry 1

First Known Use


1919, in the meaning defined above


1945, in the meaning defined above

Time Traveler
The first known use of psycho was in 1919

Dictionary Entries Near psycho

Cite this Entry

“Psycho.” Dictionary, Merriam-Webster, Accessed 6 Dec. 2023.

Kids Definition


1 of 2 noun
psy·​cho ˈsī-kō How to pronounce psycho (audio)
: a person of unsound mind
not used technically


2 of 2 combining form
: mind : mental processes and activities


short for psychopath

Combining form

derived from Greek psychē "soul, mind, principle of life"

More from Merriam-Webster on psycho

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!