What is the meaning of Lemming?

A small arctic and subarctic rodent of the tribes Lemmini, Dicrostonychini and Lagurini.

Any member of a group given to conformity or groupthink, especially a group poised to follow a leader off a cliff.

lemming (rodent)

lemming

alternative form of lémingue

lemming (rodent)

Source: wiktionary.org