Definitions of tapper:

• noun:   someone who wiretaps a telephone or telegraph wire
• noun:   a worker who uses a tap to cut screw threads
• noun:   a person who strikes a surface lightly and usually repeatedly

  Example: "Finger tappers irritated her"

• noun:   a dancer who who sounds out rhythms by using metal taps on the toes and heels of the shoes
• noun:   a tavern keeper who taps kegs or casks
• name:  A surname (rare: 1 in 100000 families; popularity rank in the U.S.: #10019)