parasite
Pronunciation:
/ˈpæɹəˌsaɪt/noun
Definitions
A person who lives on other people's efforts or expense and gives little or nothing back.
A sycophant or hanger-on.
An organism that lives on or in another organism of a different species, deriving benefit from living on or in that other organism, while not contributing towards that other organism sufficiently to cover the cost to that other organism.
Example: Lice, fleas, ticks and mites are widely spread parasites.
A climbing plant which is supported by a wall, trellis etc.