overactive
adjective
over·ac·tive
ˌō-vər-ˈak-tiv 
: excessively or abnormally active
overactive glands
an overactive imagination
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
The Immune System in Overdrive At the center of HS is an overactive immune response—one that begins with a seemingly small event inside the hair follicle.
—
Lauryn Higgins, Flow Space, 6 May 2026
Studies show the drug works by affecting brain chemicals such as glutamate and dopamine to help calm the overactive signals in the brain linked to agitation.
—Dr. Jennifer Miao, ABC News, 1 May 2026
Warm, red, thin, or smooth skin is more common with an overactive thyroid.
—Brandi Jones, Health, 28 Apr. 2026
Who Gets the Most Out of L-Theanine The evidence is clearest for people whose main sleep barrier is anxiety or an overactive mind at bedtime.
—Allison Palmer, Charlotte Observer, 23 Apr. 2026
See All Example Sentences for overactive
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.
Lauryn Higgins, Flow Space, 6 May 2026
Studies show the drug works by affecting brain chemicals such as glutamate and dopamine to help calm the overactive signals in the brain linked to agitation.
—Dr. Jennifer Miao, ABC News, 1 May 2026
Warm, red, thin, or smooth skin is more common with an overactive thyroid.
—Brandi Jones, Health, 28 Apr. 2026
Who Gets the Most Out of L-Theanine The evidence is clearest for people whose main sleep barrier is anxiety or an overactive mind at bedtime.
—Allison Palmer, Charlotte Observer, 23 Apr. 2026
See All Example Sentences for overactive
Cite this Entry
“Overactive.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/overactive. Accessed 17 May. 2026.
Copy CitationKids Definition
overactive
adjective
over·ac·tive
ˌō-və-ˈrak-tiv
: very active and especially abnormally so
an overactive thyroid
Medical Definition
overactive
adjective
over·ac·tive
ˌō-və-ˈrak-tiv
: excessively or abnormally active
an overactive mind
overactive glands
Love words? Need even more definitions?
Merriam-Webster unabridged
