What exactly is anxiety disorder?

I mean, I know what clinical anxiety is, I don't exactly mean that literally. I just mean, what is it in the sense of why is it an actual disorder? I want people to help me understand this, because it seems to be that almost everyone I know or meet says they suffer from anxiety, and they either smoke weed for it - which actually makes it worse - or they use meds.

What exactly is clinical anxiety? Why is it that so many people have it? What do you personally think it is? And what does it feel like on a regular basis? And if you have it, what do YOU do to manage it?

What exactly is anxiety disorder?
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Thanks for all the answers, everyone.
What exactly is anxiety disorder?
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