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Synonyms

overactive

American  
[oh-ver-ak-tiv] / ˌoʊ vərˈæk tɪv /

adjective

  1. exceptionally or excessively active; too active.

overactive British  
/ ˌəʊvərˈæktɪv /

adjective

  1. inordinately active

  2. (of the thyroid or adrenal gland, nervous system, etc) functioning at too high a capacity

"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

Other Word Forms

  • overactiveness noun
  • overactivity noun

Etymology

Origin of overactive

First recorded in 1640–50; over- + active

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.

The disease develops when repeated or long-term liver damage -- caused by viral hepatitis, excessive alcohol use, metabolic disorders, toxins, or autoimmune disease -- triggers an overactive healing response.

From Science Daily • Jan. 6, 2026

"I'm a fierce perfectionist and there is an overactive, hugely self-critical voice in my head - my whole life is an exercise in trying to shake that," he says.

From BBC • Dec. 31, 2025

Researchers are probing the pill’s efficacy in patients with Type 2 inflammatory diseases, which are triggered by an overactive immune response.

From Barron's • Dec. 8, 2025

“I have a prescription for an overactive bladder.”

From The Wall Street Journal • Oct. 17, 2025

It occurs when an overactive immune system begins attacking the cells that create pigment, or color, in the skin.

From "How to Disappear Completely" by Ali Standish

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.