| Infectious 1. (a.) Having qualities that may infect; communicable or caused by infection; pestilential; epidemic; as, an infectious fever; infectious clothing; infectious air; infectious vices. 2. (a.) Corrupting, or tending to corrupt or contaminate; vitiating; demoralizing. 3. (a.) Contaminating with illegality; exposing to seizure and forfeiture. 4. (a.) Capable of being easily diffused or spread; sympathetic; readily communicated; as, infectious mirth. Thesaurus Entries catching, communicable, contagious, deadly, destructive, endemic, envenomed, epidemial, epidemic, epiphytotic, epizootic, infective, inoculable, irresistible, malign, malignant, mephitic, miasmal, miasmatic, miasmic, noxious, pandemic, pestiferous, pestilent, pestilential, poisonous, sporadic, spreading, sympathetic, taking, toxic, toxicant, toxiferous, transmissible, venenate, veneniferous, venenous, venomous, virulent, zymotic |