guerrilla
Concise Oxford English Dictionary © 2008 Oxford University Press:
guerrilla /gəˈrɪlə/ (also guerilla)
▶noun a member of a small independent group taking part in irregular warfare, typically against larger regular forces.
■ [as modifier] referring to actions or activities performed in an impromptu way, often without authorization: guerrilla gigs.
– origin C19: from Sp., dimin. of guerra ‘war’.
'guerrilla' also found in these Oxford entries:
