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
• mysteriousness
• 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

Meanwhile, a fresh proposal would obligate sponsor banks to keep end-user balances at individual account level, eliminating the opacity that helped Synapse blow up. —Zennon Kapron, Forbes.com, 27 June 2025

In the long run, however, the truth emerges, and opacity and deception merely undermine trust and amplify cynicism in the political system. —Chicago Tribune, 23 June 2025

Darker shades like blue and navy are best for opacity and style, while lighter colors pair beautifully with flowy tops. —Robin Raven, Travel + Leisure, 22 June 2025

So how is it used? Gardeners should begin by understanding that the types of shade cloth typically range from 20% to 70% opacity, and the degree of shading provided by a fabric can spell the difference between a light dappling of shade and a complete shield from the sun. —Anthony Reardon, Kansas City Star, 13 June 2025

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

Rhymes for opacity

• audacity
• capacity
• loquacity
• mendacity
• pugnacity
• rapacity
• sagacity
• tenacity
• veracity
• vivacity
• voracity
• incapacity

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)