underactive

adjective

un·​der·​ac·​tive ˌən-dər-ˈak-tiv How to pronounce underactive (audio)
: characterized by an abnormally low level of activity
an underactive thyroid gland
underactivity noun

Examples of underactive in a Sentence

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.
Phytochemicals can help support balanced immune function (neither underactive nor overactive). Heather Jones, Verywell Health, 21 Feb. 2025 Hypothyroidism, or underactive thyroid, occurs when the thyroid gland doesn't produce enough hormones. Merve Ceylan, Health, 25 Jan. 2025 Interpreting Your Results Low or high TSH levels may indicate a thyroid disorder (overactive or underactive). Brandi Jones, Msn-Ed, Rn-Bc, Health, 6 Dec. 2024 Thyroid Medication Thyroid medications like Synthroid (levothyroxine) and Armour Thyroid are used to treat underactive thyroid (hypothyroidism). Alex Yampolsky, Verywell Health, 28 Oct. 2024 See All Example Sentences for underactive

Word History

First Known Use

1959, in the meaning defined above

Time Traveler
The first known use of underactive was in 1959

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Cite this Entry

“Underactive.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/underactive. Accessed 3 Mar. 2025.

Kids Definition

underactive

adjective
un·​der·​ac·​tive ˌən-də-ˈrak-tiv How to pronounce underactive (audio)
: having an abnormally low level of activity
an underactive gland

Medical Definition

underactive

adjective
un·​der·​ac·​tive -ˈak-tiv How to pronounce underactive (audio)
: characterized by an abnormally low level of activity
an underactive thyroid gland
underactivity noun
plural underactivities
Last Updated: - Updated example sentences
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