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

With the aid of his brother György, who was a dentist with a background in chemistry, Bíró set out to create a new ballpoint pen design based on viscous ink similar to newsprint. —New Atlas, 29 Oct. 2025

Small, viscous waves lapped against the shore, the swell leaving behind a brown shelf of decaying organic matter. —David Wingrave, Harpers Magazine, 24 Oct. 2025

Healthy sap is clear, viscous, and slightly golden in color. —Mary Marlowe Leverette, Southern Living, 15 Oct. 2025

Often the liquid solvent used is propylene glycol — a viscous, colorless liquid with a slightly sweet flavor. —Gabrielle Emanuel, NPR, 10 Oct. 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