What is a 환관 (宦官)?

 ANSWER: a eunuch

The Chinese character 宦 (환) means "government official," but it can also mean "eunuch" (내시 內侍), meaning "a man who has been castrated." So since 官 (관) also means "government official," 환관 (宦官) literally means "a castrated (宦) government official (官)."

Interestingly, of the nine words listed under 宦 (환) in my Chinese Character Dictionary (활용대옥편), only 환관 (宦官) is listed in my Korean-English dictionary, which defines it as "a eunuch." That suggests that the other words are not as commonly used these days.

From "활용대옥편, Chinese Characters Dictionary"