parasite

/ˈper-ə-ˌsīt/

Middle French, from Latin parasitus, from Greek parasitos, from para- + sitos grain, food

noun

  1. an organism living in, on, or with another organism in order to obtain nutrients, grow, or multiply often in a state that directly or indirectly harms the host

  2. someone or something that resembles a biological parasite in living off of, being dependent on, or exploiting another while giving little or nothing in return

Now the death of its host is certainly a setback to any parasite. To some (like the tapeworm) it is fatal; but smarter ones (like the louse) simply go off in search of a new host.

parasite sycophant toady leech sponge mean a usually obsequious flatterer or self-seeker. parasite applies to one who clings to a person of wealth, power, or influence or is useless to society. sycophant adds to this a strong suggestion of fawning, flattery, or adulation.