What does 불상사 (不祥事) mean?

Answer: a scandal; a disgraceful affair

The Chinese character 祥 (상) means a good omen, so 불상 (不祥) literally means not (不) a good omen (祥). 사 (事) means affair, matter, or business, so 불상사 (不祥事) literally means an ill-omened (不祥) affair (事)."

By the way, my Korean-English dictionary, "Dong-a's PRIME" (1998), has mistakenly listed 불상 (不祥) as 불상 (不詳), mixing up the character meaning good omen (祥) with the character meaning details or in detail (詳). The word 불상 (不詳) literally means  not (不) detailed (詳), which is often translated as unclear, unknown, or unidentified.

It is not very often that I find a mistake in my Dong-a dictionary.