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
Our amygdala is overactive, our nervous systems are fried and our dopamine cycles are hijacked by short-term stimuli.
—
Chris Schembra, Rolling Stone, 22 Oct. 2025
Typically, the immune-stimulating tactics employed in the past have either done too little to activate the immune system or done too much, triggering an overactive response that can damage the body.
—Kaitlin Sullivan, NBC news, 19 Oct. 2025
Treg cells also control internal revolt in the form of an overactive immune response by other immune cells that can trigger allergies and autoimmune diseases such as arthritis, lupus and multiple sclerosis – diseases that develop when Treg cells are defective in either number, function or both.
—Mitzi Nagarkatti, The Conversation, 10 Oct. 2025
An overactive immune system also contributes.
—Daryl Austin, USA Today, 7 Oct. 2025
See All Example Sentences for overactive
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Chris Schembra, Rolling Stone, 22 Oct. 2025
Typically, the immune-stimulating tactics employed in the past have either done too little to activate the immune system or done too much, triggering an overactive response that can damage the body.
—Kaitlin Sullivan, NBC news, 19 Oct. 2025
Treg cells also control internal revolt in the form of an overactive immune response by other immune cells that can trigger allergies and autoimmune diseases such as arthritis, lupus and multiple sclerosis – diseases that develop when Treg cells are defective in either number, function or both.
—Mitzi Nagarkatti, The Conversation, 10 Oct. 2025
An overactive immune system also contributes.
—Daryl Austin, USA Today, 7 Oct. 2025
See All Example Sentences for overactive
Cite this Entry
“Overactive.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/overactive. Accessed 24 Oct. 2025.
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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