Definitions

1. adjective

capable of being transmitted from one person or animal to another; infectious.

“The contagious laugh of her friends in the cafeteria was infectious.”

2. noun

a person or thing that is infectious.

“The contagious person in the office kept everyone home sick.”

3. verb

to communicate or spread something, especially an idea or a disease, quickly and widely.

“The rumor was contagious and spread quickly through the school.”