opaque

adjective

ō-ˈpāk 

1

: blocking the passage of radiant energy and especially light : exhibiting opacity (see opacity sense 1)

opaque glass

the opaque water of the muddy river

2

a

: hard to understand or explain

opaque prose

b

archaic : obtuse, thickheaded

opaque noun

opaquely adverb

opaqueness noun

Synonyms of opaque

• ambiguous
• cryptic
• dark
• obscure

Examples of opaque in a Sentence

In the opening hour, a group of strangers receive a maddeningly opaque cell-phone summons to join a secret cross-country race with a $32 million prize. The thing is, the summons can also be a threat (one competitor's wife is possibly being held captive), and the consequences of falling behind are murderous. —Tom Gliatto, People, 23 Apr. 2007

The reality facing Rory Stewart was that he was sent into a collapsed rural region in a country of which he knew almost nothing, and in which he had to find his way through a maze of opaque tribal and religious relationships. —Robert Skidelsky, New York Review of Books, 5 Oct. 2006

Arborio rice, the kind that grows in the Po Valley and gave rise to the wonderful dish risotto, has a tiny opaque white pearl on the inside that remains al dente, and starch on the outside that the grains release during cooking, making a creamy sauce. —Corby Kummer, Atlantic, March 1993

the opaque water of the muddy river

somehow listeners seem to connect with the songwriter, despite his deeply personal, often opaque lyrics

Recent Examples on the Web

Dozens of very luminous stellar cluster members are known, but this area likely has far more stars that are fainter hidden behind a vast smog of opaque dust between the center of the galaxy and the sun. — Phil Plait, Scientific American, 4 Sep. 2026

Silicon-photonics chips can move data using light instead of electrical signals, but conventional versions are rigid and opaque. — Neetika Walter, Interesting Engineering, 3 Sep. 2026

There are actually two new Romo models, the transparent P2 and the opaque A2. — Dominic Preston, The Verge, 3 Sep. 2026

In the 1910s, hems rose a few inches higher—in a practical and patriotic response to the Great War—and opaque fine mesh styles in geometric patterns became popular. — April White, JSTOR Daily, 2 Sep. 2026

Word History

Etymology

Latin opacus — see opacity

First Known Use

1641, in the meaning defined at sense 1

Phrases Containing opaque

• opaque projector

Rhymes for opaque

• awake
• backache
• beefsteak
• betake
• cheesecake
• cupcake
• daybreak
• earthquake
• forsake
• gouache
• handshake
• headache

Kids Definition

opaque

adjective

ō-ˈpāk 

1

: not letting light through : not transparent

2

: hard to understand

3

: dull of mind : stupid

opaquely adverb

opaqueness noun

Medical Definition

opaque

adjective

ō-ˈpāk 

: exhibiting opacity : not pervious to radiant energy

opaqueness noun