viscous

1 of 2

adjective

vis·​cous ˈvi-skəs 

1

: having a thick or sticky consistency : viscid

viscous secretions

viscous corn syrup

2

technical : having or characterized by a high resistance to flow

viscous lava

viscously adverb

viscousness noun

viscousness

2 of 2

noun

vis·​cous·​ness

plural -es

archaic

: viscosity

Synonyms of viscous

Adjective

• thick
• sticky

Examples of viscous in a Sentence

Adjective

viscous syrup that takes forever to pour from a narrow-neck bottle

Recent Examples on the Web

Adjective

That is a huge challenge, as hydrogen, natural gas, and relatively viscous kerosene behave very differently. — Georgina Jedikovska, Interesting Engineering, 28 Sep. 2026

Back at the Apollyon, Nas vomits the same black, viscous substance again. — Lexi Carson, HollywoodReporter, 25 Sep. 2026

The viscous formula is powered by four plant ferments (soybean, barley, pomegranate, and Korean pear, to name a few) and works wonders to rejuvenate skin in a single use. — Kiana Murden, Vogue, 25 Sep. 2026

The researchers linked molecules from a viscous oil and a gas to produce a new variation of this polymer, resulting in a transparent, moldable goo with a consistency similar to Blu Tack. — New Atlas, 21 Sep. 2026

Word History

Etymology

Adjective

Middle English viscouse, from Anglo-French viscos, from Late Latin viscosus full of birdlime, viscous, from Latin viscum mistletoe, birdlime; akin to Old High German wīhsila cherry, Greek ixos mistletoe

First Known Use

Adjective

14th century, in the meaning defined at sense 1

Rhymes for viscous

• discus
• hibiscus
• meniscus

Kids Definition

viscous

adjective

vis·​cous ˈvis-kəs 

1

: having the characteristic of stickiness

2

: having or marked by viscosity

Medical Definition

viscous

adjective

vis·​cous ˈvis-kəs 

1

: having a glutinous consistency and the quality of sticking or adhering : viscid

2

: having or characterized by viscosity

a viscous flow