未亡人 (미망인) literally means "still not (未) dead (亡) person (人)," but my dictionary defines it as "a widow" or "a widowed lady." It also gives the example 전쟁 미망인, which it defines as "a war widow." What bothers me about the definition is that the word literally means "undead (未亡) person (人)," not "undead (未亡) wife (妻)." The Chinese character for "wife" is 妻 (처), so why wasn't it used instead of 人 (인), which means "people"? Besides, doesn't 과부 (寡婦) already mean "widow"?
I have not really researched the word 미망인 (未亡人), but it seems like a better definition than "widow" would be "survivor," which could include anyone still living, man or woman. If 미망인 were translated as "survivor, then 전쟁 미망인 would mean "war (전쟁) survivors (미망인)," referring to people who did not die in the war. Anyway, I have a feeling that sometime in the distant past the word 미망인 was mistranslated.