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

This opacity worries Brown University psychology professor Jacqueline Nesi, who says that mental health outcomes could hinge on how the labels are applied. —Byalexandra Sternlicht, Fortune, 19 June 2024

Born into an elite family with a history of financial opacity, Sheinbaum falsely denied their involvement in the Panama Papers scandal, betraying her inclination for posverdad, or post-truth. —Kristina Foltz, The Mercury News, 7 June 2024

What to Know About Nail Polish Color Opacity Beyond choosing a color, Chue says the opacity of a nail polish formula can make or break your manicure. —Jessie Quinn, Peoplemag, 29 May 2024

Delta The opacity of the on-screen buttons can be modified in the menu. —Kyle Orland, Ars Technica, 18 Apr. 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)