yungin Share definition Flag An adolesence ranging from the ages of 13 to 18 who is very mature in what they do; a teen who's young on the outside and grown on the inside I like talking to this yungin, me and him can relate. yungin by dj32089 October 30, 2008 0 0 Get merch Get the yungin mug. Buy Now — $32.95 See more merch