Definitions of leech:

• noun:   carnivorous or bloodsucking aquatic or terrestrial worms typically having a sucker at each end
• noun:   a follower who hangs around a host (without benefit to the host) in hope of gain or advantage
• verb:   draw blood
• name:  A surname (rare: 1 in 50000 families; popularity rank in the U.S.: #5053)