undiagnosed

adjective

un·​di·​ag·​nosed ˌən-ˌdī-ig-ˈnōst How to pronounce undiagnosed (audio)
-əg-, 
-zd
: not diagnosed : not identified through diagnosis
an undiagnosed illness
… the symptoms of the syndrome may be subtle and thus may remain undiagnosed.—Dwight R. Robinson
a condition that often goes undiagnosed

Examples of undiagnosed 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.
In 1995, the death of 16-year-old John Marshall, who suffered a heart attack deriving from an undiagnosed condition known as arrhythmogenic right ventricular cardiomyopathy, proved to be a line-in-the-sand moment. — Jordan Campbell, New York Times, 6 Sep. 2026 Unraveling Medical Mysteries Patients with undiagnosed conditions suffer not only from their symptoms but also from the uncertainly of not knowing what afflicts them. — The New York Review of Books, 5 Sep. 2026 The American Academy of Sleep Medicine says undiagnosed sleep apnea alone costs the country nearly $150 billion a year, the exact condition Eight Sleep’s FDA filing targets. — Lily Mae Lazarus, Fortune, 24 Aug. 2026 In February 2023, news broke that Jansen had died suddenly at age 28 from an undiagnosed heart condition. — Brianna Zigler, Entertainment Weekly, 17 Aug. 2026 See All Example Sentences for undiagnosed

Word History

First Known Use

1864, in the meaning defined above

Time Traveler
The first known use of undiagnosed was in 1864

Browse Nearby Words

undiagnosable
undiagnosed
undialectical
See all Nearby Words

Cite this Entry

“Undiagnosed.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/undiagnosed. Accessed 7 Sep. 2026.

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Medical Definition

undiagnosed

adjective
un·​di·​ag·​nosed -ˈnōst How to pronounce undiagnosed (audio)
: not diagnosed : eluding diagnosis
undiagnosed disease
Last Updated: - Updated example sentences
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