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infectious

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infectious

  • /ɪnˈfɛk.ʃəs/ US, UK

Where it comes from

Borrowed from New Latin īnfectiōsus. By surface analysis, infect + -ious.

adjective more infectious · most infectious

  1. of an illness 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). Cancer is usually not infectious.
  2. Able to infect others; capable of transmitting pathogens. Despite feeling better, the patient is still infectious.
  3. of feelings and behaviour Spreading quickly from one person to another. infectious smile
  4. informal Memorable and invoking excitement or interest. Pop music is more infectious than elevator music.

Opposite: non-infectious, noninfectious

Thesaurus

Closest in meaning: infective, contagious, catching, communicable, septic, transmissible, transmittable, contractable, contaminating, corrupting, pathogen, infect, infectivity, infected, epidemic, viral

adjective

Opposite: non-infectious, noninfectious

Translations

Every language

adj transmitted between persons as illness

Españolinfeccioso
日本語感染性
हिन्दीसंक्रामक saṅkrāmak
Portuguêsinfeccioso
Françaisinfectieux
Deutschinfektiös
Italianoinfettivo
Românăinfecțios
Русскийзара́зный zaráznyj, инфекцио́нный infekciónnyj
العربيةمُعْدٍ muʕdin

adj able to infect others

Españolinfeccioso, contagioso
Portuguêsinfeccioso, contagioso
Françaiscontagieux
Deutschinfektiös
Italianoinfettivo, contagioso
Românăinfecțios
Русскийзара́зный zaráznyj
العربيةمُعْدٍ muʕdin

adj (of feelings and behaviour) spreading quickly between persons

Françaiscommunicatif
Deutschansteckend
Русскийзарази́тельный zarazítelʹnyj
العربيةمُعْدٍ muʕdin

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Cite this
MLA

"infectious." Wiktionary, via Micwyn, micwyn.com/word/infectious. Accessed 6 Nov. 2026.

APA

infectious. (n.d.). In Wiktionary, via Micwyn. Retrieved November 6, 2026, from https://micwyn.com/word/infectious

Chicago

"infectious." Wiktionary, via Micwyn. Accessed November 6, 2026. https://micwyn.com/word/infectious.

BibTeX
@misc{infectious_2026,
  title = {infectious},
  howpublished = {Wiktionary, via Micwyn},
  year = {2026},
  url = {https://micwyn.com/word/infectious},
  urldate = {2026-11-06}
}