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 acid also blocks tyrosinase, an enzyme involved in melanin production that can become overactive due to the body’s inflammatory response during a shingles infection.
—
Alyssa Sparacino, Glamour, 29 May 2026
Thus, people who have overactive versions of PCSK9 have fewer LDL receptors and higher LDL levels in their blood.
—Beth Mole, ArsTechnica, 28 May 2026
Sepsis is considered a life-threatening medical emergency that occurs when the body has an extreme, overactive response to an infection, causing the immune system to damage its own tissues and organs, according to the Centers for Disease Control and Prevention.
—Steve Reed, Los Angeles Times, 23 May 2026
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
See All Example Sentences for overactive
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Alyssa Sparacino, Glamour, 29 May 2026
Thus, people who have overactive versions of PCSK9 have fewer LDL receptors and higher LDL levels in their blood.
—Beth Mole, ArsTechnica, 28 May 2026
Sepsis is considered a life-threatening medical emergency that occurs when the body has an extreme, overactive response to an infection, causing the immune system to damage its own tissues and organs, according to the Centers for Disease Control and Prevention.
—Steve Reed, Los Angeles Times, 23 May 2026
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
See All Example Sentences for overactive
Cite this Entry
“Overactive.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/overactive. Accessed 6 Jun. 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
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