Gung-ho is adapted from a Chinese phrase that means, literally, work together. Brought to English during World War II by the American Lieutenant Colonel (later General) Evans Fordyce Carlson, it was originally used to describe a cooperative spirit, but it soon became a Marine battle cry. From this it developed what is now its most common sense: zealously enthusiastic. It functions usually as an adjective (e.g., “he has a gung-ho spirit”) and less often as an adverb (“he always plays gung-ho”) or a noun (“he is the biggest gung-ho of them all”).
Only two out of the 15 boys taking the poll this week expressed any yen to pursue the work that fathers toil with daily, and these two boys aren’t gung-ho over stepping into these ready-made posts. [The Robesonian (1957)]
Every pilot wanted to go. Our morale at that point was very high. Yes—you might say we were gung-ho. [Flying Magazine (1966)]
She is gung ho about tennis, however, and is the only partner who still makes time for it. [New York Magazine (1977)]
They were real gung-ho Americans, waving the flag, never questioning the government. [transcribed in American Dreams, Studs Terkel (1980)]
Pariahs of world finance they may be, but not all hedge funds are of the gung-ho, hugely leveraged type epitomised by Long-Term Capital Management. [Economist (1998)]
Reading between the lines, it seems that portion control is more the culprit than a gung-ho attitude with the butter and cream. [Guardian (2013)]