| a. | 1. | |
| 1. | Having qualities that may infect; communicable or caused by infection; pestilential; epidemic; | |
| 2. | Corrupting, or tending to corrupt or contaminate; vitiating; demoralizing. | |
| 3. | (Law) Contaminating with illegality; exposing to seizure and forfeiture. | |
| 4. | Capable of being easily diffused or spread; sympathetic; readily communicated; |
| Adj. | 1. | infectious - caused by infection or capable of causing infection; "viruses and other infective agents"; "a carrier remains infective without himself showing signs of the disease" Synonyms: infective |
| 2. | infectious - easily spread; "fear is exceedlingly infectious; children catch it from their elders"- Bertrand Russell Antonyms: noninfectious - not infectious | |
| 3. | infectious - of or relating to infection; "infectious hospital"; "infectious disease" |