Meaning : Caused by infection or capable of causing infection.
Example :
Viruses and other infective agents.
A carrier remains infective without himself showing signs of the disease.
Synonyms : infective
Meaning : Easily spread.
Example :
Fear is exceedingly infectious; children catch it from their elders.
Not infectious.
noninfectiousMeaning : Of or relating to infection.
Example :
Infectious hospital.
Infectious disease.