adjective

infectious

infectious, contagious, catching

Flu is an infectious disease.

Flu is an infectious disease.

Her laughter is infectious.

Her laughter is infectious.

an infectious ((disease/illness)) a disease that can be passed from one person to another Flu is an infectious disease.

Synonyms: contagious, communicable; (figurative) catching

From 'infect' + '-ious', an adjective-forming suffix meaning 'characterised by' or 'full of'.

The '-ious' suffix means 'full of'. So, something 'infectious' is 'full of infection' and can be passed on, like a disease or a good mood.

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