A word used when you agree with something; or when you want to recognize someone for being themselves, i.e. courageous and unique or not caring what others think. Especially common in online political slang.

The opposite of cringe, some times the opposite of biased.

The latter usage is the original use as coined by rapper Lil B, and the word originally took off on the meta-ironic website 4Chan with the latter meaning. For that reason the word is largely used meta-ironically (without context you can't tell if it's being used ironically or sincerely as it's used in both ways) and was popularized in online political slang of conservatives and the political right before being adopted into mainstream online political slang (likely through shitposting websites or subreddits such as r/politicalcompass memes that are similar to 4chan in their meta-irony and "edginess" but contain a wider variety of political beliefs) and eventually adopted into general online vernacular.

When used in online political language it can mean "based in fact" or the opposite of biased due to the number of people who saw it being first used seriously by the online political right and came to the conclusion that is was related to the phrase "destroyed with facts and logic" in reference to right wing personality Ben Shapiro.
Example 1: meta-ironic

Shitposter: Posts gif of funny monkey Return to monke
Commentor: Based

Example 2: meta-ironic
4chan Anon 1: I'm going to commit hate crimes
4chan Anon 2: Based

Example 3: Politics
Leftist 1: There is no ethical consumption under capitalism.
Leftist 2: Based.
by leftistmonke November 26, 2020
the 8 ball jacket slap is still the most based thing on the internet
by ianeaux September 17, 2020
1) true/factual. Used in political slang and used ironically in memes.
2) someone/something that is cool and/or speaks the truth
Politically
1) leftist: capitalism is bad
Leftist 2: based
2) conservative: Ben Shapiro is based.
3) leftist: socialism is based.

Ironically

Person 1: I’m gonna say the n word
Person 2: based
by the foochie January 13, 2022
to be based is to have a blood pH above the upper end of the normal range, which is 7.45. The opposite of this would be to be acidified.
Doctor: "Your blood pH is 7.41"
patient: "fuck man, i'm not based"
by Chadgtnz June 1, 2021
A strong, potentially controversial statement based in fact, made with disregard to naysayers
anon1: Love him or hate him, Donald Trump was right
anon2: Based.
by Cumconut October 13, 2022
Short for "debased," referring to a concept, object, practice or ideology that has been stripped of its intrinsic significance by association with and absorbption into the mass cultural continuum. Used meta-ironically, given that the word is itself a slang contraction and represents the debasement it seeks to impartially describe.
"Dude, I think that Nietzsche might be my favourite philosopher."
"That's based, bro."
by MajorMushroom August 20, 2018
The word 'based' when used in a sentence can mean:
- funny
- good
- cool
or any other positive remark.
Person 2: So, what did you do over the lockdown?
Person 1: I quit my porn addiction, started reading more, started lifting weights and became a religious fundamentalist.
Person 2: That's based, dude. I wish I was as based as you.
by iw035 September 21, 2020