Yippee Ki-Yay!

A relatively new Stock Phrase, usually delivered as a message of defiance or disrespect to an enemy or oppressor. In contexts where profanity is not an issue it is often followed by "motherfucker" in tribute to the Trope Maker; elsewhere, family- or kid-friendly alternatives are used, or the followup is dispensed with entirely.

The phrase originated as a cheer or cry allegedly shouted by Cowboys in the Old West; like many things from Westerns, it's probably completely fictional. The version seen in the trope name comes from "yippie yi yo kayah", part of the refrain from a 1930s Bing Crosby song, "I'm An Old Cowhand". This eventually mutated in common usage into "yippee ki-yay ki-yoh", and from there lost the last two syllables. It still retained its Cowboy connotations throughout this -- which is why it became the comeback delivered by Bruce Willis when called a "cowboy" by Alan Rickman in Die Hard.

And from there, it re-entered the meme pool with a new meaning and its original cowboy connotations mostly forgotten.

Not to be confused with Yippee Ki-Yay MF, a 2007 TV show.

Film

 * Alvin and The Chipmunks, Alvin is chased by a guard. When he finds a spotlight to use, Alvin shouts 'Yippee ki-Ya, Mamacita".
 * The Trope Maker and Trope Namer is the Die Hard series, where the entire phrase, including "motherfucker", is the Catch Phrase of John McClane, played by Bruce Willis.

Live-Action TV

 * Network broadcasts of the Die Hard films routinely censor John McClane's Catch Phrase to the inexplicable and incomprehensible "Yippee ki-yay, Mister Falcon!"

Western Animation

 * In The Loud House episode, "Cereal Offender", Lynn screams the line to market shoppers while Lincoln was doing the grocery.
 * In Big Mouth, Monster Horrensess once tells of group of kids this, right down to "motherfucker", as she and her human partner exits the school.