Hunky Dory

Boss (as an adjective)
Groovy
Bitchin’
Twitchin’
Knave
Snollygoster

She was a bitchin’ boss, but her spousal unit was a ne’er-do-well knave!

You’re thinking of antiquated Olde English.

I still use groovy sometimes.

A lot of the trendy words from my day, the 1980’s, I am happy to let die.

Interesting the word ereyesterday. I don’t remember that word, I wonder if it is old English or maybe middle English. Erev in Hebrew is the day before.

Main’t, which is the conjunction of May Not.

And ereyesterday. :)

Please and thank you.

Chiropodist, fatbacker

I’m sorry is desperately needed.

People still say thank you, but the response of you’re welcome is less common. I would not like to see a return to it, but it would be nice to have a reply to thank you. What does you’re welcome mean? You’re welcome to ask for something else?

The Spanish reply to gracias is de nada, roughly meaning, it’s nothing. That is sometimes used in English. I wonder if we could improve upon it.

If I want to use a word, I do. That’s it.

Happenstance
Fortnight ( still used in England)
Mustacheod
Fussbudget

‘Twas mere happenstance that the mustachioed fussbudget missed the fortnightly meeting!

Yonder

Ne’er do well

Scoundrel

Slacks

I still say slacks, but usually pants, but that made me think of pocket book. I think most people have been saying purse for years, but I think in the northeast pocketbook is still used. I still use it sometimes.

@JLeslie ‘Ere’ as used in a literary sense means ‘before’, as in a harvest festival hymn we used to sing in school

All is safely gathered in
Ere the winter storms begin

Britches.

Even older—Breeches!

pantaloons

@Kardamom ‘Yonder’ is still in use in some dialects in England. In my youth you could hear,

“Ha’ yer seen wor Joe?”.
“Aye, he’s owah yonder”.

American English “hoosegow” for jailer of lock-up.

Slammer.

@Dutchess_III Britches… I like! I put on my britches one britch at a time.

“Hoosegow” = “Whose cow?”