lemming

noun

Etymology: From Danish and Norwegian lemming, from Old Norse lómundr, læmingi, læmingr (“lemming”), perhaps from Sami luomek. Sense 2 derives from a longstanding myth that they exhibit so much herd mentality that populations jump off cliffs to their deaths together.

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

   “The well-known lemmings, in severe winters, at long intervals, move down from the mountains of Scandinavia in immense numbers, crossing lakes and rivers, eating their way through haystacks, and surmounting every obstacle till they reach the sea, whence very few return.”

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

   “Lemmings are strongly cohesive, but could be, in organisational terms, highly destructive for the business.”

   “Like a lemming, I followed the crowd, got to the right line and was concentrating hard when queried by the customs officer.”