Sloth comes from Middle English slowth, slewthe, from Old English slǣwth ('laziness'), from slǣw, slāw ('slow') plus the noun suffix -th. The historical chain includes Old English slāw. Older glosses in the chain include "laziness" and "slow", which help explain the semantic range of the modern word. Morphologically, sloth is best read as suffixal formation and borrowing, yielding an English noun shaped by both form history and later usage. In current English it functions as a noun, with the sense "habitual laziness; also a slow-moving tropical mammal". English derivatives include slothful and slothfulness; related forms include slow. The result is an English noun whose etymology preserves the older forms while supporting the word's specialized modern meaning.