Her knight-errantry in trying to solve all social problems single-handedly was admirable but unrealistic.

knight-errantry 是由 knight（骑士）和 errantry（游侠行为）组成的复合名词。knight 指中世纪欧洲的骑士阶层，errantry 来自动词 errant（漫游的），指骑士四处游历、行侠仗义的行为。 knight-errantry 特指中世纪骑士那种四处游历、行侠仗义的作风，后来引申为"侠义精神"或"不切实际的行侠仗义行为"。