https://www.merriam-webster.com/dictionary/parasite
parasite noun
par·a·site | \ ˈper-ə-ˌsīt , ˈpa-rə- \
Definition of parasite:
1: a person who exploits the hospitality of the rich and earns welcome by flattery
2: an organism living in,
with, or on another organism in parasitism
3: something that resembles a biological parasite in dependence on something else for existence or support without making a useful or adequate return