Antonyms of adj infectious

2 of 3 senses of infectious

Sense 1
infectious, infective -- (caused by infection or capable of causing infection; "viruses and other infective agents"; "a carrier remains infective without himself showing signs of the disease")

INDIRECT (VIA septic) -> antiseptic -- (thoroughly clean and free of or destructive to disease-causing organisms; "doctors in antiseptic green coats"; "the antiseptic effect of alcohol"; "it is said that marjoram has antiseptic qualities")

Sense 2
infectious (vs. noninfectious) -- (easily spread; "fear is exceedingly infectious; children catch it from their elders"- Bertrand Russell)

noninfectious (vs. infectious) -- (not infectious)
        => noncommunicable, noncontagious, nontransmissible -- ((of disease) not capable of being passed on)

Similarity of adj infectious

3 senses of infectious

Sense 1
infectious, infective -- (caused by infection or capable of causing infection; "viruses and other infective agents"; "a carrier remains infective without himself showing signs of the disease")
       => septic (vs. antiseptic), infected -- (containing or resulting from disease-causing organisms; "a septic sore throat"; "a septic environment"; "septic sewage")

Sense 2
infectious (vs. noninfectious) -- (easily spread; "fear is exceedingly infectious; children catch it from their elders"- Bertrand Russell)
       => catching, communicable, contagious, contractable, transmissible, transmittable -- ((of disease) capable of being transmitted by infection)
       => contagious -- (easily diffused or spread as from one person to another; "a contagious grin")
       => corrupting, contaminating -- (that infects or taints)

Sense 3
infectious -- (of or relating to infection; "infectious hospital"; "infectious disease")