Ellie Rasmussen, 22, and Spencer Schramm, 21, have been dating for almost two years.

They tell people they met at a college party, but they actually found each other on a dating app, where they gradually transitioned from messaging and Snapchatting to the holy grail: texting. A few months later, they started dating.

"He waited a while, but it was still cute," said Rasmussen. "He actually had rizz. He asked me to my face if I wanted to be his girlfriend."

Is rizz something to want in a significant other? Why yes, since it's the new shorthand for charisma.

TikTok users are excited to share their rizz via extravagant serenading skills, ideal pickup lines for every personality type and (hopefully!) flawless moves. But to have rizz, you only need to be suave, confident, flirty and not too egotistical. Having rizz requires being charming yet approachable, easy to talk to.

Why pack all of that into a four-letter word?

Anatoly Liberman, a professor in the University of Minnesota's Department of German, Nordic, Slavic and Dutch, understands.

"English is a monosyllabic language," he said. "When there is a long word, speakers will try to curtail it and turn it into a monosyllable. And if they use slang, this tendency is reinforced by the fact that slang is informal and it's more radical than the rest of the language."

Other examples of shortened words include "husband" to "hubby," "doctor" to "doc," "laboratory" to "lab," and "spectacles" to "specs."

"If you take a word like charismatic, it's sort of bookish, and it is very long. And slang wants the word to be short, and then you begin to cut it to one syllable," he said. "If you take the form "charisma," then you have a stressed syllable — exactly what you need. Take a syllable and use it as a word."

While rizz is the current go-to word on social media, Liberman can't predict how long it'll remain popular. If he had to guess, he'd put money on it being short-lived, in use for a couple of months or years.

Condensed words, he said, eventually "die because they are not witty, they are not interesting, and, as far as the etymology is concerned, they're all of the same type," he said.

For their part, Rasmussen and Schramm are working to keep their rizz alive as long as possible.

"Doing new things and doing things that we like to do, that keeps a relationship fun and exciting," said Schramm.