敲 means to knock or tap (e.g., on a door) and is the general word for this action. It differs from 点 (a brief touch with a finger) and 打 (a stronger strike with wider usage, like hit or beat). It also colloquially means to overcharge or rip someone off, similar to 宰—but 敲 is common for service overcharge, while 宰 implies more aggressive gouging.