Word family noun infection disinfectant adjective infectious infected verb infect ≠ disinfect adverb infectiously
From Longman Dictionary of Contemporary Englishinfectiousin‧fec‧tious /ɪnˈfekʃəs/ ●○○ adjective 1 MIan infectious illness can be passed from one person to another, especially through the air you breathe infectious diseases Flu is highly infectious.2 MIsomeone who is infectious has an illness and could pass it to other people3 SPREADinfectious feelings or laughter spread quickly from one person to another an infectious smile infectious enthusiasm —infectiously adverbExamples from the Corpus
infectious• Heavy drinkers are generally more susceptible to infectious diseases.• Doctors say that the disease is most infectious in the first twenty-four hours.• Sheila has an infectious smile.• The vaccine protects against Hepatitis B, a highly infectious virus.highly infectious• The nasal discharge and the discharge from the abscesses is highly infectious and this is how strangles is spread to other horses.• The countryside has been virtually shut down in a bid to contain the highly infectious disease.• Foot and mouth disease is caused by a highly infectious virus which animals either eat or inhale.infectious smile• He was a snub-nosed little fellow in a grubby shirt, with an infectious smile.• His infectious smile and sense of fun was highly reminiscent of Gedge anyway. 