What does 혼족 mean?

ANSWER: a tribe of loners

The slang phrase 혼족 refers to people who like doing things alone. The 혼 in the word comes from the pure Korean word 혼자, which means "alone," and the 족(族) is a Sino-Korean word that means "tribe," so 혼족 literally means "a tribe of loners," which is oxymoronic since loners do not associate as a group. Here the word "tribe" just refers to similar-minded people. Other similar slang words that describe what loners do are 혼밥, 혼술, and 혼놀.

혼밥 means "eating alone," with the 밥 being the pure Korean word for "boiled rice" or "food." 혼술 means "drinking alone," with the 술 being the pure Korean word for "wine," "alcohol," or "liquor." And 혼놀 means "enjoy doing things alone," with the 놀 coming from 놀다, which is a pure Korean verb meaning "to play."

For more information on the words, Wikipedia has a rather lengthy English explanation of them HERE.