aback

The dictionary definition of “aback” is an adverb meaning to be taken by surprise or caught off guard.

Use cases:

-When someone unexpectedly receives shocking news, they might be taken aback.

-A sudden change in plans can leave someone feeling taken aback.

Examples In Sentence:

1. Sarah was taken aback by the sudden resignation of her boss.

2. The unexpected arrival of guests left the hostess momentarily taken aback.