- communicable by infection, as from one person to another or from one part of the body to another: infectious diseases.
- causing or communicating infection.
- tending to spread from one to another: infectious laughter.
- Law. capable of contaminating with illegality; exposing to seizure or forfeiture.
- Obsolete. diseased.
Origin of infectious
SynonymsSee more synonyms for on Thesaurus.com
1. See contagious.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for infectious
For most infectious, the amount is 100 or even 1,000 times that.A Doctor Explains Why Cruise Ships Should Be Banned
November 19, 2014
The only existing study, printed in the Journal of Infectious Diseases in 1999, leaves scientists with the same questions.Blood Is Ebola’s Weapon and Weakness
October 26, 2014
Adam Lausing, an infectious disease researcher at the University of Michigan, emphasized that Ebola is not a respiratory disease.Fact-Checking the Sunday Shows: October 19
October 19, 2014
Any time there is a new outbreak of infectious disease, it can be alarming.What You Need to Know About Enterovirus
October 3, 2014
Strict isolation of patients; good clinical care; and rapid, culturally sensitive disposal of infectious cadavers.1976 Vs. Today: Ebola’s Terrifying Evolution
September 10, 2014
"Evidently, of an infectious fever as your Eminence so well says," he replied.The Three Cities Trilogy, Complete
As the doctor declared it not infectious, I was allowed to nurse him.Wilfrid Cumbermede
The laugh was so infectious that even Brown was obliged to smile.The Woman-Haters
Joseph C. Lincoln
It automatically cleanses the wound of any infectious matter.'Smiles'
Eliot H. Robinson
Her happiness was infectious, and Sarah turned to her visitor with an amused smile.Sarah's School Friend
- (of a disease) capable of being transmittedCompare contagious
- (of a disease) caused by microorganisms, such as bacteria, viruses, or protozoa
- causing or transmitting infection
- tending or apt to spread, as from one person to anotherinfectious mirth
- international law
- tainting or capable of tainting with illegality
- rendering liable to seizure or forfeiture
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for infectious
Online Etymology Dictionary, © 2010 Douglas Harper
- Capable of causing infection.
- Caused by or capable of being transmitted by infection.
- Caused by a pathogenic microorganism or agent.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
- Capable of causing infection. See Note at contagious.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.