Having qualities that may taint, or communicate disease to; as an infectious fever; infectious clothing; infectious air; infectious miasma.

Corrupting; tending to taint by communication; as infectious vices or manners.

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

Capable of being communicated by near approach. Grief as well as joy is infectious.