Dictionary.com
definitions

punji stake

[poo n-jee, puhn-]
noun
  1. a sharp bamboo stake concealed in high grass at an angle so as to gash the feet and legs of enemy soldiers and often coated with excrement so as to cause an infected wound.

Origin of punji stake

1870–75; earlier punjee, panja, perhaps < Chingpaw, a Tibeto-Burman language of the Kachins of NE Burma and adjacent areas of India and China; the word is first attested in an account of these people
Also called punji stick.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018