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• unheard-of
  unheard-of

  adjective

  that was never heard of; unknown.
• unheard of
  unheard of

  Very unusual, extraordinary, as in It's unheard of to have all one's money refunded two years after the purchase. This expression alludes to a circumstance so unusual that it has never been heard of. [Late 1500s]

unheard-of

American  

[uhn-hurd-uhv, -ov, -uhv] / ʌnˈhɜrdˌʌv, -ˌɒv, -əv /

adjective

1. that was never heard of; unknown.

   an unheard-of artist.

2. such as was never known before; unprecedented.

   an unheard-of salary.

3. shocking or outrageous.

   unheard-of conduct.

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unheard-of British  

adjective

1. previously unknown

   an unheard-of actress

2. without precedent

   an unheard-of treatment

3. highly offensive

   unheard-of behaviour

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unheard of Idioms  

1. Very unusual, extraordinary, as in It's unheard of to have all one's money refunded two years after the purchase. This expression alludes to a circumstance so unusual that it has never been heard of. [Late 1500s]

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Etymology

Origin of unheard-of

First recorded in 1585–95

Example Sentences

See Examples For:

unheard-of unheard of

On Wednesday, Five Below reported nearly 23% same-store sales growth, an unheard-of number for a retailer that is now 23 years old.

From Barron's ● Jun. 5, 2026

"That's an unheard-of pace of innovation in developing complex structural alloys."

From Science Daily ● Mar. 10, 2026

She also commissioned original scores from American composers, choosing to use contemporary music from her own country—an unheard-of thing to do when she began, Ross says.

From The Wall Street Journal ● Jan. 25, 2026

His thesis at the Navy Academy was in the unheard-of topic of liquid-fuel engines.

From BBC ● Aug. 9, 2025

Even Father, whose daily stroll was as predictable as his own clock chimes, broke his routine to go walking at the unheard-of hour of 10:00 a.m.

From "The Hiding Place" by Corrie ten Boom

Schroden said he had seen "reports of similar events occasionally over the past couple of decades" and that "it's rare but not unheard of, though tragic in every case."

From Barron's ● Aug. 13, 2026

That's a remarkable step - pretty much unheard of in terms of mid-season upgrades.

From BBC ● Jul. 28, 2026

Legal experts said such an action is unheard of.

From Los Angeles Times ● Jul. 28, 2026

Professional-services firms have so many training off-sites that having such a facility isn’t unheard of.

From The Wall Street Journal ● Jul. 24, 2026

Like the desolation of some alien sea breaking on the shores of a world unheard of.

From "The Road" by Cormac McCarthy

Related Words

• exceptional
• inconceivable
• little-known
• unbelievable
• undiscovered
• unprecedented