Used after a sarcastic retort to inform those too stupid to detect sarcasm by themselves. This is never spoken, only written, and generally only used in online forums or instant messenging and such.
Person A: You're so smart.
Person B: Thanks.
Person A: Whoops, forgot to include my sarcasm tags. <sarcasm> You're so smart. </sarcasm>
by Join the Alliance. August 26, 2006
Used in chats and conversations every day, "</sarcasm>" is used to denote sarcasm. In HTML programming, tages are ended with a "/", such as </b> for bold text. Usually one would say a sarcastic remark, and then use </sarcasm> to indicate that he has finished his sarcasm. It pwns your mom.
Yeah, I DIDN'T do you mom last night.

by backtothefuture October 24, 2003
Inspired from BB code, sarcasm/sarcasm are used to denote sarcastic passages in one's text when their nature is rendered ambiguous by the inability of varying tone of voice or communicating exaggerated gestures, as would be the case in person-to-person conversation. This is especially useful when the said passages could easily be misinterpreted as offensive, dimwitted or otherwise unfunny. While perfectly acceptable on the internet, the use of "bracket sarcasm end-bracket" in day-to-day conversation is considered socially awkward and should be refrained from.
Usage of sarcasm/sarcasm:

sarcasm"Insert text here"/sarcasm

Example :

"sarcasmOh my! It appears as if the oil industry is once again taking initiatives to save the environment. They have our best interests at heart and never buy patents for ludicrous sums of money that would otherwise render their industry unprofitable./sarcasm

(Notice this is the end of the sarcastic passage and the beginning of the normally-read passage)

I'm white and love grape soda.

(This passage was NOT sarcastic)"
by DeLorean_4 December 22, 2011
The ability to insult idiots without them realizing it.
Idiot: I beat up a ten year old today.
You: That's impressive! (with a hint of sarcasm)
Idiot: I know, right!
by Adrusi December 31, 2011
A tongue of which the user speaks of something the complete opposite of what the user means. It often has the best comedic value.
Ex. 1: "I'm okay. Don't mind the gaping wound and the sword protruding from my back. I'm fine. Feel like a million fucking bucks, dammit."

Ex. 2:
"Is your car stuck in the mud?"
"No, no, of course not. I'm only practicing how to spray mud using my tires.

by Drake Aldan April 6, 2004
Mom: how was school today, son?
Son: it was fuckin' great, mom.
by Prosciutto Bellino January 18, 2004
Your body's natural defense against stupid.
You walk into a hospital room where your friend is on a bed with his left leg, no arms, and only half of his prick. You say,"How ya doin, man?"
He says,"Oh, just great. I feel better than ever. I could just hop all around the world, I feel so great."
You say,"Really? That's some great news."

See, this isn't your friend trying to make you look stupid, which if you said one or both of these things, you might be, it was his immune system acting due to the high levels of stupidity being taken into his brain. It automatically responded with sarcasm. So don't take it personaly.
by Big Jew February 23, 2007