overactive

adjective

over·​ac·​tive ˌō-vər-ˈak-tiv How to pronounce overactive (audio)
Synonyms of overactivenext
: excessively or abnormally active
overactive glands
an overactive imagination
overactivity
ˌō-vər-ak-ˈti-və-tē How to pronounce overactive (audio)
noun

Synonyms of overactive

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Examples of overactive in a Sentence

She has an overactive bladder. His crazy ideas are products of an overactive imagination.
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
In the nineties, Edenberg helped identify genetic differences linked to overactive ADH enzymes, which would cause people to turn alcohol into acetaldehyde more quickly. — Shayla Love, New Yorker, 26 Aug. 2026 Consuming superpotent thyroid tablets can cause an overactive thyroid and issues like weight loss, heat intolerance, fatigue and hypertension, according to the notice. — Melina Khan, USA Today, 25 Aug. 2026 People with atopic dermatitis also have an overactive immune system, which can trigger inflammation. — Ayren Jackson-Cannady, Allure, 20 Aug. 2026 Psoriasis is a chronic disease in which the immune system becomes overactive, causing inflamed, scaly patches of skin. — Grace Gavilanes, PEOPLE, 18 Aug. 2026 See All Example Sentences for overactive

Word History

First Known Use

1647, in the meaning defined above

Time Traveler
The first known use of overactive was in 1647

Rhymes for overactive

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Browse Nearby Words

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Cite this Entry

“Overactive.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/overactive. Accessed 1 Sep. 2026.

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Kids Definition

overactive

adjective
over·​ac·​tive ˌō-və-ˈrak-tiv How to pronounce overactive (audio)
: very active and especially abnormally so
an overactive thyroid
overactivity
-rak-ˈtiv-ət-ē How to pronounce overactive (audio)
noun

Medical Definition

overactive

adjective
over·​ac·​tive ˌō-və-ˈrak-tiv How to pronounce overactive (audio)
: excessively or abnormally active
an overactive mind
overactive glands
overactivity
-ˌrak-ˈtiv-ət-ē How to pronounce overactive (audio)
noun
plural overactivities
Last Updated: - Updated example sentences
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