■ noun
1》 an organism which lives in or on another organism and benefits by deriving nutrients at the other's expense.
2》 derogatory a person who habitually relies on or exploits others and gives nothing in return.
Derivatives
parasiticide noun
Origin
C16: via L. from Gk parasitos '(person) eating at another's table', from para- 'alongside' + sitos 'food'.