Parasite vs. Pathogen

Parasitenoun

(pejorative) A person who lives on other people's efforts or expense and gives little or nothing back.

Parasitenoun

(pejorative) A sycophant or hanger-on.

Parasitenoun

(biology) An organism that lives on or in another organism, 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.

Parasitenoun

A climbing plant which is supported by a wall, trellis etc.

Parasitenoun

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.

Parasitenoun

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

Parasitenoun

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.

Parasitenoun

an animal or plant that lives in or on a host (another animal or plant); the parasite obtains nourishment from the host without benefiting or killing the host

Parasitenoun

a follower who hangs around a host (without benefit to the host) in hope of gain or advantage

Pathogennoun

Any organism or substance, especially a microorganism, capable of causing disease, such as bacteria, viruses, protozoa or fungi. Microorganisms are not considered to be pathogenic until they have reached a population size that is large enough to cause disease.

Pathogennoun

Any microorganism which causes disease; a pathogenic organism; an infectious microorganism; a bacterium, virus, or other agent which can cause disease by infection; - opposed to zymogene. The spelling pathogene is now archaic.

Pathogennoun

any disease-producing agent (especially a virus or bacterium or other microorganism)

Pathogen

In biology, a pathogen (Greek: πάθος pathos , and -γενής -genēs ) in the oldest and broadest sense, is any organism that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ.