aback:
be taken aback (by something)
:to be very surprised or shocked by something
For a moment, I was completely taken aback by her request
Sentences from books, newspapers, etc.
He seemed even more taken aback than I was, and this heartened me.
He was momentarily a bit taken aback.
Intel was taken aback by the intensity of public anger.
She appeared taken aback, as if she had only just realised that the pair of them were not alone.
The authorities were taken aback, and took the unprecedented step of cordoning off the painting.
The singer is capable of delicacy, as well; the occasional pianissimo utterance takes you aback.
They all looked suitably taken aback by his entrance, muttering disapproval whilst he insisted that Ockleton step outside.
Though she did seem taken aback, come to think of it.