opaque

Use the adjective opaque either for something that doesn't allow light to pass through (like a heavy curtain) or for something difficult to understand (like bureaucratic gobbledygook).

Opaque is from a Latin word meaning "dark," and that was its original sense in English, but it now means literally "not transparent" or metaphorically "hard to understand; unclear": "Some of his sentences are really opaque." It used to be spelled opake, which made the pronunciation clearer, but we then borrowed the more opaque French spelling. Come to think of it, English spelling is often pretty opaque, which makes it hard for learners of the language to master.

Definitions of opaque
1

adj not transmitting or reflecting light or radiant energy; impenetrable to sight

opaque windows of the jail”
opaque to X-rays”
Synonyms:
unclear
not clear to the mind
cloudy, mirky, muddy, murky, turbid
(of liquids) clouded as with sediment
fogged, foggy
obscured by fog
frosted
(of glass) having a roughened coating resembling frost
glaucous
having a frosted look from a powdery coating, as on plants
light-tight, lightproof
not penetrable by light
milklike, milky, whitish
resembling milk in color not clear
semiopaque
partially opaque
solid
impenetrable for the eye
Antonyms:
clear
allowing light to pass through
crystal clear, crystalline, limpid, lucid, pellucid, transparent
transmitting light; able to be seen through with clarity
hyaline, hyaloid
resembling glass in transparency or translucency
limpid, liquid
clear and bright
semitransparent, translucent
allowing light to pass through diffusely
unclouded
not made opaque or cloudy by sediment
unfrosted
(of glass) lacking a frosted coating
show more antonyms...

adj not clearly understood or expressed

Synonyms:
unintelligible
incomprehensible, uncomprehensible
difficult to understand

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