Wordorigins.org

The sense of the word commando, meaning an elite soldier, appeared during the Second World War with the raids on occupied France by elite British forces of that name. Winston Churchill wrote to General Ismay on 2 July 1940:

If it be true that a few hundred German troops have been landed on Jersey or Guernsey by troop-carriers, plans should be studied to land secretly by night on the islands and kill or capture the invaders. This is exactly one of the exploits for which the Commandos would be suited.