Meaning & use

infectious

adjective·Academic

Capable of being transmitted as a disease, or spreading quickly from one person to another.

See it in a sentence

The doctor confirmed the illness was infectious and advised the whole family to stay home.

Her infectious laughter soon had everyone in the meeting smiling too.

A note on using this word

For diseases spread through the air or contact, infectious and contagious overlap, but infectious more often describes moods or enthusiasm too.

Words with a similar meaning

contagiouscommunicable

Choose a synonym to suit the sentence. Meanings can overlap without being identical.

Words with an opposite meaning

noninfectious

Another way to use it

2. adjective

Spreading rapidly among people because it is appealing or exciting, as an attitude or emotion.

His infectious enthusiasm for the project convinced the entire team to work through the weekend.

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