viscous
Americanadjective
-
of a glutinous nature or consistency; sticky; thick; adhesive.
-
having the property of viscosity.
adjective
-
(of liquids) thick and sticky; viscid
-
having or involving viscosity
Other Word Forms
Etymology
Origin of viscous
1350–1400; Middle English < Late Latin viscōsus, equivalent to Latin visc ( um ) mistletoe, birdlime (made with mistletoe berries) + -ōsus -ous
Explanation
Viscous means sticky, gluey and syrupy. So if something is viscous, you usually don't want to stick your fingers in it — that goes for boogers and maple syrup alike. Not quite a solid and not quite a liquid, scientists like to say that viscous things don't flow very easily. They glop and slug around slowly, sticking to whatever they come in contact with. Think of making a batch of Rice Krispie treats: One minute the marshmallows are solid little rounds; the next minute they're melted into a web of sticky white goo that's somehow attached itself to the Rice Krispies, the spoon, the countertops, your nose, the front door, and the dog.
Vocabulary lists containing viscous
The Vocabulary.com Top 1000
Looking to grow your vocabulary? Check out this interactive, curated word list from our team of English language specialists at Vocabulary.com – one of over 17,000 lists we've built to help learners worldwide!
Grade 11, List 6
Interested in learning more words like this one? Our team at Vocabulary.com has got you covered! You can review flashcards, quiz yourself, practice spelling, and more – and it's all completely free to use!
Stroke of Genius: Words About Painting
Want to remember this word for good? Start your learning journey today with our library of interactive, themed word lists built by the experts at Vocabulary.com – we'll help you make the most of your study time!
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Uganda's oil is particularly viscous and must be kept at 50C to be transported through the pipeline.
From Barron's ● Sep. 2, 2026
The thought is that donating blood reduces iron levels and makes the blood less viscous; thicker blood is associated with a higher risk of blood clots and heart attacks.
From Slate ● May 9, 2026
"It will also be interesting to see how this finding may be applied to assist fiber spinning and other applications that use viscous liquids."
From Science Daily ● Mar. 30, 2026
American fuel makers are snapping up the rising supplies of Venezuela’s heavy, viscous oil that their refineries were designed to process.
From The Wall Street Journal ● Mar. 5, 2026
She was swallowed, lost in a viscous haze, shrouded in a soup of nothingness.
From "Americanah" by Chimamanda Ngozi Adichie
![]()
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.