infectious
Proposed by a contributor, not yet supported by evidence.
Sense 1
Caused by an agent that enters the host's body (such as a bacterium, virus, parasite, or prion); often, also, transmitted among hosts via any of various routes (for example, contact, droplet-borne, airborne, waterborne, foodborne, fomite-borne, or bloodborne).
Adjective
Examples
Usage example from English Wiktionary (CC BY-SA 4.0, retrieved 2026-08-01)
Sources & notes
Adapted from English Wiktionary (CC BY-SA 4.0, retrieved 2026-08-01 via kaikki.org).
Sense 2
Able to infect others; capable of transmitting pathogens.
Adjective
Examples
Usage example from English Wiktionary (CC BY-SA 4.0, retrieved 2026-08-01)
Sources & notes
Adapted from English Wiktionary (CC BY-SA 4.0, retrieved 2026-08-01 via kaikki.org).
Common questions
What does “infectious” mean?
Caused by an agent that enters the host's body (such as a bacterium, virus, parasite, or prion); often, also, transmitted among hosts via any of various routes (for example, contact, droplet-borne, airborne, waterborne, foodborne, fomite-borne, or bloodborne).
Is “infectious” formal or informal?
No register label has been reviewed yet — treat it as neutral and check the usage notes above.