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 noun

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.
There are reasons to believe CAR-T therapy may be able to target the same overactive B cells that current multiple sclerosis drugs already do. Kaitlin Sullivan, NBC news, 15 Mar. 2026 Where Co-Existing Conditions Come In There are also skin conditions that affect Black women at higher rates, including melasma, which can cause discoloration from overactive pigment cells. Iyana Robertson, Flow Space, 10 Mar. 2026 Koy, the son of a white father and Filipina mother, saw comedy as a way to channel an overactive personality and need to make people laugh into a career. Deputy Entertainment, Los Angeles Times, 5 Mar. 2026 Is this all lip service, or will those living near the buzz of an overactive data center actually see relief? Rob Pegoraro, PC Magazine, 5 Mar. 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

Browse Nearby Words

Cite this Entry

“Overactive.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/overactive. Accessed 17 Mar. 2026.

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 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 noun
plural overactivities

More from Merriam-Webster on overactive

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