Infectious

Part of speech: adjective (a.)

1. Having qualities that may infect; communicable or caused by infection; pestilential; epidemic; as, an infectious fever; infectious clothing; infectious air; infectious vices. Where the infectious pestilence. Shak.

2. Corrupting, or tending to corrupt or contaminate; vitiating; demoralizing. It [the court] is necessary for the polishing of manners . . . but it is infectious even to the best morals to live always in it. Dryden.

3. Contaminating with illegality; exposing to seizure and forfeiture. Contraband articles are said to be of an infectious nature. Kent.

4. Capable of being easily diffused or spread; sympathetic; readily communicated; as, infectious mirth. The laughter was so genuine as to be infectious. W. Black.

Synonyms: See Contagious.