gung-ho
Concise Oxford English Dictionary © 2008 Oxford University Press:
gung-ho /gʌŋˈhəʊ/
▶adjective unthinkingly enthusiastic and eager, especially about taking part in fighting or war.
– origin Second World War: from Chin. gōnghé, taken to mean ‘work together’ and adopted as a slogan by US Marines.
'gung-ho' also found in these Oxford entries:

