opacity

noun

opac·​i·​ty ō-ˈpa-sə-tē 

plural opacities

1

a

: obscurity of sense : unintelligibility

b

: the quality or state of being mentally obtuse : dullness

2

: the quality or state of a body that makes it impervious to the rays of light

broadly : the relative capacity of matter to obstruct the transmission of radiant energy

3

: an opaque spot in a normally transparent structure (such as the lens of the eye)

Synonyms

• ambiguity
• ambiguousness
• darkness
• equivocalness
• equivocation
• inscrutability
• inscrutableness
• murkiness
• mysteriousness
• nebulosity
• nebulousness
• obliqueness
• obliquity
• obscurity
• opaqueness

Examples of opacity in a Sentence

the opacity of the glass

Critics have noted the opacity of her writing style.

Recent Examples on the Web

Many cases have been for 500-pound bombs, said a U.S. official, who like others spoke on the condition of anonymity because of the sensitivities and opacity around arms sales. —Edward Wong, New York Times, 6 Apr. 2024

Many in this city of skeptics question how well the MTA will spend the money, given its history of mismanagement, graft, and opacity. —Hillary Chura, The Christian Science Monitor, 2 Apr. 2024

Next was the water’s opacity: The thick sediment blinded Rambelli and Felipe, researchers at the Federal University of Sergipe, just feet beneath the surface. —Rafael Vilela, Washington Post, 31 Mar. 2024

What percentage of ground glass opacities are cancerous? —Leah Groth, Health, 30 Mar. 2024

Individuals appreciate having choice in their health care, but opacity often increases money spent because our employers can’t keep track of the best value for the cost. —Benjamin Chartock, STAT, 13 Mar. 2024

But one area where Jenner opted to be a little more conservative was the dress’s opacity. —Hannah Jackson, Vogue, 11 Mar. 2024

Joseph’s Omid exudes a smiling reverence, but his friendliness has an opacity that grows in intrigue. —Charles McNulty, Los Angeles Times, 7 Feb. 2024

The refinery also violated standards for opacity and visible emissions standards involving smoke, ash and soot, according to a news release from the state health department detailing the settlements. —Noelle Phillips, The Denver Post, 5 Feb. 2024

Word History

Etymology

Middle French opacité shadiness, from Latin opacitat-, opacitas, from opacus shaded, dark

First Known Use

1575, in the meaning defined at sense 1a

Kids Definition

opacity

noun

opac·​i·​ty ō-ˈpas-ət-ē 

plural opacities

: the quality or state of being opaque

Medical Definition

opacity

noun

opac·​i·​ty ō-ˈpas-ət-ē 

plural opacities

1

: the quality or state of a body that makes it impervious to the rays of light

broadly : the relative capacity of matter to obstruct by absorption or reflection the transmission of radiant energy (as X-rays, infrared radiation, or sound)

2

: an opaque spot in a normally transparent structure (as the lens of the eye)