The proper way to express how you don't give a crap about something - you really don't care about something and it's impossible to not care any more. The common but incorrect variant "could care less" (which would technically imply that you do care about something) is widely used because of either a translation mistake into English, or those who blindly use phrases without taking a moment to understand their actual meaning.
Person A: A company just got sued for patent infringement!
Person B: *yawn* Oh really? I couldn't care less.
by generic June 10, 2006
Get the couldn't care less mug.
Other: "Oh my gosh, did you hear about Jennie and her..."
Me: "Oh my gosh, did you hear abut the time that I couldn't care less?"
Other: "No"
Me: "Oh, well it's now :)"
by Don't give a fuck December 16, 2016
Get the couldn't care less mug.
A phrase meaning "The degree to which I care about this could not possibly go lower." Most people naturally interpret it to mean "I care about this as little as any human could; my degree of care is 0".

But it can also be interpreted to mean "I care about this to a certain extent (which may be a little or a whole lot) and there is no way in hell my caring is ever going to drop."

Arguments about this can get pretty heated, with Team Couldn't Care Less tending to care more.
"Guess what happened on Dancing with the Stars last night?"
"Please don't bother me with that, I really couldn't care less about it."

"Mr. Politician, do you care about America?"
"I'm glad you asked that. I care about America more than anything in the world, and I couldn't care less, not in a million years. You'll have to pry my care from my cold dead hands."
by Lenoxus July 5, 2012
Get the couldn't care less mug.
The classier (and cleaner) way to say "I don't give a fuck", "I don't give a shit", "I don't give a crap", "I don't give a damn", etc.

(Do NOT confuse it with I could care less. If you *could* care less, it means that you can reduce the amount of fucks you give!)
"The Dvorak Keyboard lets you type comfortably because the keys are positioned so that the fingers can-"
"I couldn't care less."
by cutesy pastel living doll November 6, 2013
Get the I couldn't care less mug.
A phrase that emphasises the lack of care for something or someone. Often mistaken as 'I could care less'.
David: Quick Bert! Muffles the kitten ate some mothballs, and now it's foaming out it's mouth; WE NEED TO GOTO A VET!

Bert: I couldn't care less about your God-Damned Cat right now.
by SeanJohn August 3, 2006
Get the I couldn't care less mug.
The correct version of i could care less. Something to say when you really don't care about something/someone.
person 1: My phone died :(
person 2: I could really care less.
person 1: No! its "i couldn't care less", if you're going to not care, at least do it right!

person 2: i don't care.
by tenyaiida July 8, 2020
Get the I couldn't care less mug.