Regards with astonishment

GAPESAT

Think of how someone might stare in wide-eyed wonder at something unbelievable.

"Regards with astonishment" hints at a word meaning to stare in wide-eyed wonder. The answer "GAPESAT" breaks down into "GAPE" (to stare in amazement) and "SAT" (past tense of "sit"), but the trick is that "SAT" here isn’t part of the meaning—it’s just there to complete the word. Think of it like "gape" wearing a little hat ("at") to form a longer word, even though the clue only cares about the "gape" part.