What's the origin of the word flabbergasted?

Search: flabbergasted etymology

Why: It's how I felt about this video:

I mean, can you imagine? But also when I told Joel I felt that way, I spelled it with an "h" (after the "g").

Answer: Nobody knows. Doy.

It turns up first in print in 1772, in an article on new words in the Annual Register. The writer couples two fashionable terms: “Now we are flabbergasted and bored from morning to night”. (Bored — being wearied by something tedious — had appeared only a few years earlier.)

It may be linked to a old dialect word flabrigast. Maybe part of it is flabby, like shaken + aghast, shocked or horrified.

Here is an image that comes up if you Google "flabbergasted."

Source: World Wide Words

The More You Know: Do you know what that word "aghast" reminds me of? If you guessed Les Miserables, you are right.

I am agog, I am aghast
Is Marius in love at last?
I've never seen him ooh and ahh
You talk of battles to be won
But here he comes like Don Ju-an
It's better than an opera