Parasite

Part of speech: noun (n.)

1. One who frequents the tables of the rich, or who lives at another's expense, and earns his welcome by flattery; a hanger-on; a toady; a sycophant. Thou, with trembling fear, Or like a fawning parasite, obey'st. Milton. Parasites were called such smell-feasts as would seek to be free guests at rich men's tables. Udall.

2. A plant obtaining nourishment immediately from other plants to which it attaches itself, and whose juices it absorbs; -- sometimes, but erroneously, called epiphyte.

3. A plant living on or within an animal, and supported at its expense, as many species of fungi of the genus Torrubia.

4. An animal which lives during the whole or part of its existence on or in the body of some other animal, feeding upon its food, blood, or tissues, as lice, tapeworms, etc.

5. An animal which steals the food of another, as the parasitic jager.

6. An animal which habitually uses the nest of another, as the cowbird and the European cuckoo.