Not quite Pedants Corner, but perhaps worth a ponder?

Awfully

Bounder

SPIV

Jolly and Chaps.
I use both and get funny looks.
I think the old words are a bit Public School.

Chums

I often use the word "chap". I ordered a bathrobe for Mr P once, and had "Best Chap" embroidered on it!

Ghastly was one of my mother’s commonly used words, often combined with “little man” when referring to any politician to the left of Genghis Khan
Jolly good
Spiffing
Bounder
Lashings (of cream etc)

Oh my conscience my DMILs favourite saying

Spiffing!
The Bees Knees and the Cats Pyjamas
High jinks
Here's to more colourful language

Rotter

Splendid

Swot

Smashing
Ripping
Golly
Jolly

Balderdash!
Floozie (I love that one)
Ragamuffin
Toodle pip (old fruit)
Flibbertigibbet

I still use spiv, for any bloke who looks and acts like one.

Love flibbertigibbet Witzend so descriptive

Old thing - affectionate term
Jolly hockey sticks - girls school
Old bean - friendly term

I still use jolly, and gosh, (but not together) and crickey! (that doesn't look as though it's spelled right?)

Oh dear! I still use beastly, ghastly jolly, smashing, splendid, chap, chums and Oh my giddy Aunt! Several friends (chums) do likewise.

A Billy Bunter expression Phoenix think its crikey though.

Fit as a flea!

My German friend had never heard it before despite living here for 50 years

Ha ha! I use lots of these words I'm afraid.
Showing my age, obviously. Though my youngest daughter uses quote a few too and she's only 30!

Goodo! My DIL 's mother says frightfully

Oh. I use lots of these words. I model myself on the aunts that Mr PG Wodehouse writes about so splendidly don't you know.

Yikes
Blimey
Toodle do (not sure that’s the accurate spelling)
Harlot
Twerp
Noggin

Ngaio1 and CherryCezzy I still use a lot of those words and I certainly didn't go to public school.

Many years (40) ago I read that expressions such as 'Crikey', 'Blimey' and 'Struth' come originally from people swearing informal oaths to confirm they were telling the truth.

'Crikey' - may Christ kill me if I'm lying.
'Blimey' - may God blind me if I'm lying.
'Streuth' - that is God's truth.

I'd be interested to know if others have heard this. There's a lot on the Internet but most is unreliable.

I use quite a few of those words, sometimes not entirely seriously.

I'm listening to an audiobook just now, set in the 40s, where people have been described as being quite gay.

“Bristol bright”, toffs, dosh

FarNorth Being pedantic here.

I can't see any reason why 'gay' cannot mean both happy and homosexual in context.

After all, the word 'book' has many different meanings. Likewise: bat, key, try, push, card etc., so why not 'gay'?

My mother always said "Perish the day". . I haven't heard that in a long while.
She also told us about ' Crikey etc Bradfordlass, and we were not allowed to say them. Though my Dad often said " Crikey Moses".
I had a friend who shouted " Horlicks" when she was cross. Very effective.