sapper
noun
1
a Viet Cong or North Vietnamese commando. Members of the North Vietnamese Army's combat engineers, and thus the name, derived from the longstanding UK sense of the word as 'a soldier in the Engineer Corps, the Royal Sappers and Miners'. 'Sappers inside the wire!' was a warning call that US soldiers did not want to hear US, 1987.
2
during the Vietnam war, an Australian combat engineer, especially one who searched and destroyed enemy tunnels AUSTRALIA, 1990