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 of opacity

• 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

Taken together, the federal actions reflect a clear shift toward greater scrutiny of PBMs and specifically the extraordinary opacity of the system in which these intermediaries operate. —Joshua P. Cohen, Forbes.com, 1 June 2026

Financial regulations must be strengthened to reduce opacity in chip funding and exposure to public assets, limiting potential fallout. —Rakesh Kumar, Fortune, 30 May 2026

Some have been more vocal than others, publicly chastising him for his opacity ahead of what is expected to be a competitive general election race. —Connor Greene, Time, 29 May 2026

Those arrangements create much pricier options for ultrawealthy fans, take the burden of selling some seats off the rights holder and create more opacity in the market, blurring the line between what inventory is unsold by a group like FIFA and what’s unsold via a hospitality partner. —Sara Germano, Sportico.com, 28 May 2026

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
• fugacity
• loquacity
• mendacity
• 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)