When someone is astonished, they are very surprised. They might be surprised by the unexpectedness of the situation, or by the severity of the situation.
She was astonished when she found out that her house was burned down.
I was astonished when I saw the size of the earthquake.
adjective
filled with the emotional impact of overwhelming surprise or shock
Synonyms:
1
One of the meanings of disbelief is 'amazement, astonishment'.
2
It is much to his own surprise and the astonishment of comrades, friends and family
3
It's the principle of least astonishment.
4
The absurdity of this decision is astonishing.
5
The amount of confusion is astonishing.
6
The persistence of this illusion is astonishing.
7
He stared at the figure in astonishment.
8
I am astonished at the credulity.
9
The astonishment is all on the other side.
10
The urgent news astonished the people.