sloth

American  

[slawth, slohth] / slɔθ, sloʊθ /

noun

1. habitual disinclination to exertion; laziness; indolence.

   Indifference, negligence, and sloth have no place in the classroom.

   Synonyms:

   idleness

2. any of several slow-moving, arboreal, tropical American edentates of the family Bradypodidae, having a long, coarse, grayish-brown coat often of a greenish cast caused by algae, and long, hooklike claws used in gripping tree branches while hanging or moving along in a habitual upside-down position.

3. a pack or group of bears.

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sloth British  

/ sləʊθ /

noun

1. any of several shaggy-coated arboreal edentate mammals of the family Bradypodidae, esp Bradypus tridactylus ( three-toed sloth or ai ) or Choloepus didactylus ( two-toed sloth or unau ), of Central and South America. They are slow-moving, hanging upside down by their long arms and feeding on vegetation

2. reluctance to work or exert oneself

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Etymology

Origin of sloth

First recorded in 1125–75; Middle English slowth; replacing Old English slǣwth, derivative of slǣw, variant of slāw “slow”; slow, -th ¹

Explanation

If you lounge around in your bathrobe watching TV and ordering out for pizza, you'll get called a sloth. A sloth is actually a slow-moving, tree-dwelling mammal, but it has become a synonym for "lazybones." Slug also doubles as the name of an animal and a term for someone who is lazy, slow or lethargic. But with slug, the animal name probably morphed into the human application, whereas sloth has meant "lazy person" or "laziness" for a long time. In the Catholic Church sloth was categorized as one of the seven deadly sins.

Example Sentences

In one case, a nest was discovered inside the pulp cavity of a sloth tooth.

From Science Daily • Apr. 3, 2026

A mother sloth shelters her baby from a downpour at La Selva Biological Station, Costa Rica.

From BBC • Mar. 25, 2026

Researchers in Costa Rica have unearthed fossils from a mastodon and a giant sloth that lived as many as 40,000 years ago, officials announced Friday, calling it the biggest such find here in decades.

From Barron's • Feb. 13, 2026

I would wake earlier, but I think in a past life I was a two-toed sloth or something because I’m nocturnal and I move very slowly.

From Los Angeles Times • Dec. 12, 2025

The skull belonged to a megatherium, a mammoth version of a sloth.

From "The Gene" by Siddhartha Mukherjee