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  • hyper
    hyper
    adjective
    overexcited; overstimulated; keyed up.
  • hyper-
    hyper-
    a prefix appearing in loanwords from Greek, where it meant “over,” usually implying excess or exaggeration (hyperbole ); on this model used, especially as opposed to hypo-, in the formation of compound words (hyperthyroid ).
  • hyper–
    hyper–
    A prefix that means “excessive” or “excessively,” especially in medical terms like hypertension and hyperthyroidism.
Synonyms

hyper

1 American  
[hahy-per] / ˈhaɪ pər /

adjective

  1. overexcited; overstimulated; keyed up.

  2. seriously or obsessively concerned; fanatical; rabid.

    She's hyper about noise pollution.

  3. hyperactive.


noun

  1. a person who is hyper.

hyper 2 American  
[hahy-per] / ˈhaɪ pər /

noun

Informal.
  1. a person who promotes or publicizes events, people, etc., especially one who uses flamboyant or questionable methods; promoter; publicist.


hyper- 3 American  
  1. a prefix appearing in loanwords from Greek, where it meant “over,” usually implying excess or exaggeration (hyperbole ); on this model used, especially as opposed to hypo-, in the formation of compound words (hyperthyroid ).


hyper 1 British  
/ ˈhaɪpə /

adjective

  1. informal overactive; overexcited

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

hyper- 2 British  

prefix

  1. above, over, or in excess

    hypercritical

  2. (in medicine) denoting an abnormal excess

    hyperacidity

  3. indicating that a chemical compound contains a greater than usual amount of an element

    hyperoxide

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

hyper– Scientific  
  1. A prefix that means “excessive” or “excessively,” especially in medical terms like hypertension and hyperthyroidism.


Etymology

Origin of hyper1

First recorded in 1970–75; probably independent use of hyper-

Origin of hyper2

1910–15, for an earlier sense; hype 1 + -er 1

Origin of hyper-3

Greek, representing hypér over, above; cognate with Latin super ( see super-); akin to over

Explanation

Someone who's hyper is overly excited or energetic. If coffee and tea make you feel a little hyper, you might try switching to decaf! Hyper is a shortened form of hyperactive, a behavior that includes restlessness and sometimes inappropriate amounts of movement. It's part of an official diagnosis, attention deficit hyperactivity disorder, or ADHD. But hyper also describes any excessive activity or feeling or excitability: "I want one of these sleepy kittens, not those hyper ones climbing the curtains." The Greek root of hyper means "too much," and when someone is hyper, they really are too much!

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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.

In 2027 or early 2028, Japanese forces will bring to Kyushu another new homegrown missile—the Hyper Velocity Gliding Projectile, designed to evade enemy defenses—after deploying one in central Japan this year.

From The Wall Street Journal • Mar. 31, 2026

The scientists are building Hyper K - which will be a bigger and better version of their existing neutrino detector, Super K.

From BBC • May 12, 2025

Among them is the Hyper Tourer minivan concept that Nissan says has advanced technologies like autonomous driving.

From Seattle Times • Oct. 24, 2023

Seated on the hard sidewalk along Cahuenga Boulevard, Rue Ryan arranged a batch of red roses she had plucked from the trash into a memorial for her “street mom,” Hyper, who died two years ago.

From Los Angeles Times • Dec. 22, 2022

He now made a proper addition to the general atmosphere of these meetings on Hyper Base.

From "I, Robot" by Isaac Asimov

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