tap at

tap at (something)

To strike something lightly, swiftly, and repeatedly. You're never going to drive the stake into the ground tapping at it with your hammer like that. I could have sworn I heard someone tapping at the window, but there was no one there when I got up to check.See also: tap

tap at something

to make one or more light blows on something. Fred tapped at the door, but no one heard him. Who is tapping at my window?See also: tap