bloodsucking

from The Century Dictionary.

• Sucking or drawing blood; preying on the blood: as, “blood-sucking sighs,”

from the GNU version of the Collaborative International Dictionary of English.

• adjective drawing blood from the body of another.
• adjective having the nature or habits of a parasite or leech; living off another; -- of plants or persons.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective of an animal That draws off the blood of another animal
• adjective by extension, of a person parasitic, leechlike or freeloading

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective of plants or persons; having the nature or habits of a parasite or leech; living off another
• adjective drawing blood from the body of another