Definition

Smallest, either in size or degree; shortest; lowest; most unimportant; as, the least insect; the least mercy; the least space.

Other Definitions

This word also has 2 other definitions:

LEAST (adverb)

In the smallest or lowest degree; in a degree below all others; as, to reward those who least deserve it.

LEAST (conjunction)

See Lest, conj. [Obs.] Spenser.