For my grandmother slang was a four-letter word. She didn't want slang in the dictionary because she thought it infected our language.
"He goes", "she goes", "they go"; but no one goes anywhere. Because enough people used the word goes incorrectly for a long enough period of time, the goes that means says goes into Webster's Dictionary - and there goes our language.
When I wasn't looking, the adjective "pretty" morphed into a noun, a verb AND an adverb; and they all got into the dictionary. Pretty is as pretty does - noun. Pretty yourself up - verb. Pretty soon - adverb. If people were more careful how they used words, pretty would still be just another pretty word.
The word very isn't slang and it isn't used incorrectly, but it's been used so much it's become hackneyed. If an adjective isn't preceded by very, it's like a retired boxer who's lost his punch.
However, miniscule sounds much smaller than very small; colossal sounds much bigger than very big; and although antiquated means very old, it sounds older.
"Have a nice day" is an example of a hackneyed expression. It's a nice thought; but it's been used so much, it's become synonymous with good bye. It's lost its niceness.
"Just a second" is not only hackneyed, it's also highly improbable. Who can do anything in a second? Saying "Just a minute" might be improbable too, but you're sixty times more likely to be accurate.
Accuracy is in the dictionary; but unfortunately, it's slipping from our language. Nevertheless, there is a good word about words. Not all illegitimate words have been legitimized by Webster's.
My 2002 edition defines "postal" as relating to mail or post offices. It does NOT define it as relating to someone who has suddenly gone crazy. That definition of postal comes from common usage. It's not a new word. Mad originally meant insane; but because of common usage, it's been demoted to angry.
A coined word is a new word and I've coined one. My word replaces the often misused "unbelievable". If you are aware of something with one or more of your senses or if you trust the source of your information, it can't be unbelievable.
What it can be is "hardtobelievable". If enough people use my word for a long enough period of time, hardtobelievable might get into the dictionary - but I'm not sure Grandmother would be proud.