About "giddy" meaning "playful and silly" - for native English speakers
I’m a little unsure about one of the meanings of “giddy” and wondering if there might be a difference between US and UK English. Merriam-Webster Learner’s dictionary has:

1
: playful and silly

giddy children
giddy antics
a giddy atmosphere

On the other hand Oxford Learner’s dictionary has

4. (old-fashioned) (of people) not serious, synonym silly:

Isabel’s giddy young sister

On the other hand Oxford Learner’s dictionary has

2. [not usually before noun] giddy (with something): so happy and excited that you cannot behave normally:

She was giddy with happiness.

So I get the impression that you wouldn’t use “giddy” before a noun to mean silly as in “giddy children” in current UK English (since it's old-fashioned), but you would in US English. And what about “giddy antics” and “a giddy atmosphere”?

Anyone who can enlighten me a bit about this?
Thanks for your help!

Question

About "giddy" meaning "playful and silly" - for native English speakers
I’m a little unsure about one of the meanings of “giddy” and wondering if there might be a difference between US and UK English. Merriam-Webster Learner’s dictionary has:

1 
: playful and silly

giddy children
    giddy antics
    a giddy atmosphere

On the other hand Oxford Learner’s dictionary has

4. (old-fashioned) (of people) not serious, synonym silly:

Isabel’s giddy young sister

On the other hand Oxford Learner’s dictionary has

2. [not usually before noun] giddy (with something): so happy and excited that you cannot behave normally:

She was giddy with happiness.

So I get the impression that you wouldn’t use “giddy” before a noun to mean silly as  in “giddy children” in current UK English (since it's old-fashioned), but you would in US English. And what about  “giddy antics” and “a giddy atmosphere”?

Anyone who can enlighten me a bit about this?
Thanks for your help!

Answer

Can't comment on US usage. But as a British English speaker, I would use giddy in phrases like 'giddy with success', 'giddy with delight', or, 'giddy from...' I am feeling giddy from spinning on the roundabout'. I don't think I have ever heard an expression 'giddy +noun'.

Answer

I agree that it is quite old-fashioned and unlikely to be used in day to day speak! (I'm from the UK).

You may read it in novels, or perhaps in a satirical context it could be used... perhaps as a sarcastic response you could say you're 'giddy with delight' or 'giddy' at the prospect of something.

It's similar to being dizzy, but 'giddy' is quite a quaint and fairly dated way of expressing that feeling.

Similarly, to describe someone as 'giddy' means they're a bit scatty, excitable, perhaps all over the place, a bit 'dizzy' or unreliable and child-like and bouncy, but again it's not something you'd really say these days. I can't remember the last time I heard, read or used the word!

Hope that helps!

Answer

I wouldn't use 'giddy' in any of those ways. They all sound like something from another era.

Isabel's giddy young sister probably did something outrageous like drinking lemonade in public without her gloves on.

For me, 'giddy' is a feeling rather than a personality or behavourial trait. It's similar to dizzy - a slight feeling of nausea and lightheadedness, like when you get off a fairground ride.