Ahjinssi is a combination of the name Jin (A member of the kpop boy group BTS) and Ahjussi which means 'uncle,' but is the formal way to refer to a older man that you don't know well (kinda like 'Sir' in English). This started being used because when Jin is angry or flustered, he sounds like an old man and tends to yell or lecture the person bothering him about what they're doing.
Ahjinssi can be used for anyone who get's angry/flustered easily and makes a big deal out of whatever is bothering them(usually by yelling). It can also be used for someone who in general acts like an uncle/Dad, going strong with the dad jokes.
A nice, kind, considerate girl, that is very smart. she gets along with everyone, is super sweet and loves to play netball with her friends, but still aces every test
“Wow did you see Anjika get 99% on that test?”
“She’s also supernice too!!”
Created by the Japanese as a nickname since when you say "Asian Kung", it sounds like Ajikan. This was then used as their nickname.
#1: Have you seen the new Blackout PV by Ajikan?
#2: Who is Ajikan?
#1: Oh, it's Asian Kung-Fu Generation.
#2: Haha, where'd you pick that up from?
#1: Some dude named Chris defined it at Urbandictionary.com.