How often "bid adieu" is used in English?

Pretty much everybody will understand it, but I've only heard it used in theatrical performances or shows. It's the kind of thing I'd associate with an old-timey emcee.

I feel like it would be extremely bizarre for anyone below 40. Even above 40 it's self-consciously jokey and silly. At least in American English where French classes are quite niche and it just doesn't carry the same cultural cachet as 50 or 75 years ago. Even without the French, I think "say goodbye" has pretty much replaced "bid farewell".

It reminds me of Britain around the World War period, and I don't know why.

I think most people in the UK would understand it from context, but it's not something you'd use day-to-day. It's something you'd use to sound a little bit fancy or make a slightly showy exit. For example, if I had been visiting my grandma and maybe stayed little longer than I intended, I might say "Well, I'm going to bid you adieu" give a hug "I'll let you know when I get home safe". Or, if I was out with my friends but needed to leave earlier than them, I might say "Okay I have to get going, so I'm going to say adieu and you guys don't get into too much trouble without me."

I would only ever use it humourously

It's theatrical and showy and so there will be times when it's fun to use. "I bid you ADIEU". Not sure if Gene Wilder said it in CATCF but he should have done.

We had a bet on a game. The wager was a can of Mountain Dew. My team lost, so I paid up. When paid up, I put the can on his desk and said "I bid you a Dew."

It’s something you’ll see in comedy shows or very dramatic people. Not in day to day 

I don't think I've ever heard someone say it in real life. Only in books or movies.

I don't think I have seen anybody use it unironically.

I have literally never heard it here in Canada. I just had to google what it meant.

It won’t be universally understood. I’d assume anyone who said it was being silly or overly dramatic as a joke.

I use it when I'm feeling fancy, usually in a joking manner Everyone would know what it means tho

It’s old fashioned but people sometimes say it for fun. “I bid thee adieu.” If you say it to bookworms or other intellectual folk at the end of a game of chess or bridge or dungeons and dragons, it’ll go over well. If you say it when you just watched a football game with them, it’ll seem quite out of place.

most will understand it, but very few will actually use it day-to-day

I would understand it, but have never heard it and would certainly never use it.

I don’t hear it often at all, tbh. My one friend will say it but he also went to college for theatre arts lol and my other friend says it bc he does D&D all the time and finds it appropriate. I’ve heard it at some super high class social events. That’s pretty much it.

Rarely, of course.

Its not commonly used, but I think most people have heard it at least once in a cartoon or whatever, so they will know what it meant.

Never heard it in 32 summers floating about in London

“I must away ‘ere break of day, adieu adieu adieu.”

Not often. People would know what you meant but I can’t remember the last time someone said it to me in conversation unless trying to sound posh. Also it’d usually be ‘bid you adieu’ as in ‘I bid you adieu’

Seldom to rarely to never.

Maybe I am the only english speaker here that doesn’t recognize this phrase so I don’t know what it means lol. But it seems like most other people would understand

You wouldn’t, except maybe ironically.

TL;DR basically never from modern speakers unless they're being ironic. Throughout history, English (and its older forms) has had the habit of borrowing French words to sound fancy. "Bid adieu" or "I bid you adieu" is an old phrase that leans into that in a rather pompous way. You'll pretty much only encounter it in theatre, poetry, melodramatic 1950s films, and period pieces from the Victorian Era or earlier, or as self-referential humour/irony because it sounds so pompous. "Adieu" is French for "farewell" or "goodbye" (it actually comes from a longer phrase that means "I commend you to God" - here, "commend" takes a rare/archaic meaning similar to "entrust", such as in the phrase "Father, into thy hands I commend my spirit" from the KJV translation of the Bible, but I digress). "Bid" in this context is being used with the archaic meaning "to express [a greeting, farewell, benediction, or wish]". So, broken down, it would be something like "I am saying that I wish for you to have a safe journey under the protection of God." Now, is this the actual meaning that a modern speaker will attribute to it? No, because its constituent parts are either archaic or a shortened phrase from another language; much of the original meaning will be completely lost on modern speakers. They'll understand it as a fancy way of saying "goodbye" that has an overly theatrical flair because nobody has seriously talked like that for 100 years. Side note: "Farewell" also has archaic origins and sounds fancy/old, though not AS fancy as "adieu" or as pompous as "I bid you farewell", and could simply be used for formal effect. Really, it's the grammatical imperative "fare well". "Fare" takes the archaic meaning "travel" and "well" is the adverb counterpart of "good". So "have a good trip" or "get home safe(ly)" would be more idiomatic to modern speakers, depending on context.

It's kind of ridiculous-sounding. I've only ever seen it in fiction, and the last time I remember seeing it being used was in a video game [as a translation for japanese ごきげんよう, a nearly equally ridiculous phrase](https://imgur.com/a/9xVlCm5).

It is only used in a very pedantic matter where someone is trying to sound much more sophisticated than they actually are, same with most French borrowed phrases. They are also usually misused and pronounced horribly.

I would use it to flirt or to pretend sounding formal in a situation that is not formal. In the latter, if I am at work at the end of a busy day and a work-buddy is leaving I might use 'adieu' as a sort of light joke to imply we are parting on good terms.

You mean, "How often is 'bid adieu' used in English?"

It’s very informal but some people use it

It's old English, but people do understand it. You'll probably get looked as a bit of a posho if you use it