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1. A polite way of saying "go fuck yourself", "fuck you", or even just "goodbye". Short form for "light your ass/self on fire".

2. A way of saying "thank you".
EXAMPLE 1
You: Stop being a bitch.
Me: Light it.

EXAMPLE 2
You: Dinner's on me tonight.
Me: No, you paid last time.
You: No, seriously.
Me: Light it.
light it by LB79 September 2, 2006

Light It. 

1. A polite way of saying "go fuck yourself", "fuck you", or even just "goodbye". Short form for "light your ass/self on fire".

2. A way of saying "thank you".
EXAMPLE 1
You: Stop being a bitch.
Me: Light it.

EXAMPLE 2
You: Dinner's on me tonight.
Me: No, you paid last time.
You: No, seriously.
Me: Light it.
Light It. by LB79 September 15, 2008

Light It. 

1. A polite way of saying "go fuck yourself", "fuck you", or even just "goodbye". Short form for "light your ass/self on fire".

2. A way of saying "thank you".
EXAMPLE 1
You: Stop being a bitch.
Me: Light it.

EXAMPLE 2
You: Dinner's on me tonight.
Me: No, you paid last time.
You: No, seriously.
Me: Light it.
Light It. by LB79 September 16, 2008

Light it up blue 

A slogan used by hate group Autism Speaks to promote finding a cure for autism. As a result its better to go REDInstead.
Person 1: Let's light it up blue for Autism!
Person 2: No you asshole! Let's go REDInstead

Light It Up 

Direct a lot of machine gun fire at it.
<car approaching checkpoint>
Sergeant: "Fire warning shots."
<car keeps coming>
Sergetant: "Light it up."

...1000 rounds later...

Private: "Shit, shit, that car was full of orphans and nuns. Dammit!"
Light It Up by joej30983hn February 13, 2006

light it up red 

A slogan that supports autistic people to freely express themselves. This goes in contrast to "light it up blue" which only promotes the awareness of autism, even though almost everyone has at least heard of autism by now. "light it up red" however, promotes respect and acceptance towards autistic individuals and is a more meaningful way to promote the autistic community.
Red is the color of love, ambition, and respect. Blue is the color of disappointment and depression. Lets light it up red instead to let everyone know that the autistic community is capable of understanding and respect.
light it up red by Dubiks December 6, 2018
More from Urban Dictionary

Pee Calculus

When you have to pee in a movie but don’t want to miss anything, and must do the following mental equation: will the amount I have to pee cause enough discomfort to diminish my attention capacity for the remainder of the movie to an extent which is greater than the amount of the movie I would miss by making a mad dash to the restroom.
I saw Satantango last night, wonderful film but by the 5th hour I had to start doing pee calculus.
Pee Calculus by anorlondo October 1, 2026
Word of the Day on October 2, 2026
Literally "dirty" pronounced with a West Indian accent. Can also have a positive connotation, for example Sean Paul's album title "Dutty Rock".
"The girl is pretty but she corrupt and dutty!"

or, in a positive usage:

"Booya! That freestyle was dutty!"
Dutty by J Hall April 3, 2003
Word of the Day on October 1, 2026
korean word for madam, older woman
Ajumma wait a moment
Ajumma by aintnotinbutnice July 5, 2009
Word of the Day on September 30, 2026

Slop Grenade

When someone uses AI to generate a large document, slide deck, or piece of code/software and tosses it over the fence for you to deal with.
Chad: Hey Brent I sent you the new backend API change to review, it’s only 100 files changed.

Brent: he just tossed me a slop grenade
Slop Grenade by Joe Squid September 28, 2026
Word of the Day on September 29, 2026
Short-hand for the word floccinaucinihilipilification, meaning the estimation of something as valueless (encountered mainly as an example of one of the longest words in the English language).
After we broke up, he was floxi to me.
floxi by Dr. Geek May 13, 2009
Word of the Day on September 28, 2026
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