viscous

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

Synonyms of viscous

• thick
• sticky

Examples of viscous in a Sentence

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

Recent Examples on the Web

Adding that there were multiple bloods; some waterier, some viscous, others stickier, Flanagan explained that blood for dropping was different from what needed to be painted on Howell, which could not drip off. — Alex Zalben, IndieWire, 9 Oct. 2026

This one appears quick opaque and viscous, but actually does a nice job at melting down onto the skin and absorbing quickly. — Lucy Partington, Glamour, 7 Oct. 2026

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

Word History

Etymology

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

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