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

• thick
• sticky
• syrupy

Examples of viscous in a Sentence

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

Recent Examples on the Web

The palate is flavorful and creamy, with an oily, viscous mouthfeel, showcasing notes of dark chocolate, fig, raisin, white pepper, and a hint of mint. —Joseph V Micallef, Forbes.com, 31 May 2025

For example, the magma nearest the surface of the Yellowstone Caldera contains a lot of silica, which lends the molten rocks a sticky, viscous, and slow-moving quality. —Paul Smaglik, Discover Magazine, 3 Jan. 2025

This is a much more viscous material that does not flow very readily and, instead, can cause explosive eruptions. —Ars Technica, 3 Jan. 2025

Etna's lava flows are also normally viscous and slow-moving, often allowing authorities to intervene to redirect flows that threaten communities. —Bill Chappell, NPR, 2 June 2025

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
• viscus
• 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