Definitions of piercing:

• adjective:   high-pitched and sharp

  Example: "Piercing screams"

• adjective:   loud and sharp

  Example: "The piercing shriek of sirens"

• adjective:   suitable for cutting or piercing

  Example: "The piercing needle"

• adjective:   as physically painful as if caused by a sharp instrument

  Example: "Piercing knifelike pains"

• adjective:   having or demonstrating ability to recognize or draw fine distinctions