Someone who is obsessed with Korean culture so much they denounce their own culture and call themselves Korean. They usually are kpop fanatics (not fans) or fans of League of Legends or other competitive games popular in South Korea. However there is a line; if someone just likes the music, language and culture they are not classed as a koreaboo.
"That boy over keeps calling himself Korean and all he talks about is Korean things, he's such a koreaboo!"
by j.wang21 October 21, 2017
Someone who denounced their own race and calls themselves Korean, genuinely believes that they’re Korean or wishes they were Korean. They may also think that they will some day marry their favourite idol (see also delulu) or may use small parts of Korean in their sentences without caring about learning the language. They could think that all Asians/Koreans are beautiful gods who are above the human race (see also yellow fever).

Not someone who:
-is interested in Korean culture
-listens to Kpop music
-listens other Korean music genres
-watches Korean TV shows
-makes cringey jokes about Korean celebrities
-wants to live in Korea
“Jackie is such a Koreaboo, she’s American she shouts ‘OPPA’ at random Asian men and tries to look Korean by glueing her eyelids down.”
by Healing Smile January 1, 2019
Someone who is obsessed with Korean culture (not north, but south) and talks about them non-stop. Probably won't see them ever again, because while you are reading this, they have immigrated to Seoul.
Why are you such a Koreaboo! I'd rather you be a weeaboo!
by bobster1001 May 26, 2017
Someone who no lifes Korean Dramas and music, and wants to wife Kim Ji Won.
John Alemu is a Koreaboo
by DrizzyDrakeinthe6 April 5, 2018
A website that posts inaccurate stuff and starts fandom wars in the Korean music industry.
Only thing Koreaboo knows how to do is source from "Netizens".

Koreaboo posted another bullshit headline again.
by SMKoon December 30, 2016
Koreaboo is a shit website that doesn't give any accurate information and cries "Netizens" all the time. Koreaboo also loves to start fan wars.
John: whatcha reading?
Mary: just another shit article by Koreaboo claiming Netizens claimed Koreaboo is the most accurate website
John: Mary get your shit together
by Koreaboosuxdick December 30, 2016