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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.

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.

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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.

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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 ).

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hyper- ¹ 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

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hyper ² British  

/ ˈhaɪpə /

adjective

1. informal overactive; overexcited

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hyper– Scientific  

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

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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!

Example Sentences

"When we inactivate these neurons, the mice become hyper distractable," Kothari said.

From Science Daily • Jun. 24, 2026

Vance said Trump was "hyper aware" of the issue.

From Barron's • May 13, 2026

"More than half experienced physical symptoms including difficulty sleeping, headaches or excessive tiredness, while nearly two thirds reported behavioural changes such as distrusting others or hyper vigilance," Halkon said.

From BBC • Apr. 12, 2026

In this room, I am at times unsettled, at once tracking the movements of the actors while attempting to remain hyper aware of any sudden touch or scent.

From Los Angeles Times • Mar. 26, 2026

They’re hyper, huddled together and squirming around like a bunch of preschoolers.

From "Like Vanessa" by Tami Charles

Related Words

• aggressive
• alive
• bold
• busy
• determined
• diligent
• dynamic
• eager
• energetic
• engaged
• enthusiastic
• forceful
• intense
• keen
• lively
• quick
• ready
• resolute