1. A derogatory word for people which is used in the sense of physical or mental inactivity: Sloths are reluctant to do whatever work that they should be doing.

The term sloth is a stronger word than "idle" or "lazy". Historically, it is one of the Seven Deadly Sins.

2. One of several slow moving animals that live in the trees in South American forests: On a recent expedition to South American, a biologist counted three different types of sloths living in the trees.
3. Etymology: from Middle English slouthe, "slow".