Addendum

I realize nobody uses hep anymore, but by the time science fiction happens, it might be back.

Don't Get Left Behind

OUT: Wizard
ALL ABOUT: Magic-haver

Period Piece Implementation

If you write something that takes place in, say, 1168, make sure to have people speak appropriately for the era. "Out of sight," "mod," "shemozzle," and "whirligig" are just a few of the things they should say.

The Best Science Fiction Predicts Future Social Trends

And that's why I'm telling you right now that people will say "Bonanza!" as sort of a slang thing. If not, that's how we'll know humanity took the wrong path. Perhaps we should reset this world to zero.

An Example

"You gotta spin out that clingety to spin axles, 'ceive?"

This means, "You perceive, do you not, that I demand to be paid money in exchange for employing my coach in carrying passengers?" A common statement rendered immersive and invigorating by the appropriate terminology.

Proper Terminology

What not to call money if you're trying to sound fantasy-y: Coin.
What to call money if you want to immerse people in your amazing fantasy world: Clingety.