形容词

1. （病）接触传染的
A disease that is contagious can be caught by touching people or things that are infected with it.

2. (感情、态度等)感染性的，会迅速蔓延开的
A feeling or attitude that is contagious spreads quickly among a group of people.

1. (of disease) capable of being transmitted by infection

Synonym: catchingcommunicablecontractabletransmissibletransmittable

2. easily diffused or spread as from one person to another

e.g. a contagious grin