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infectious

adj.
US //ˌɪnˈfɛkʃəs// UK //ɪnfˈɛkʃəs// in·fec·tious
  1. 1 medical/disease (adj.)
    B2 Upper Intermediate Technical Medicine

    describes a disease that can be passed from one person to another through germs or viruses.

    relating to a disease caused by a pathogen that enters the body and is capable of being transmitted to other hosts.

    Example

    The doctor warned that the flu is highly infectious during the first few days.

    Example

    Public health officials monitored the outbreak closely, concerned by how infectious the new strain appeared to be in densely populated urban areas.
  2. 2 spreading feelings (adj.)
    B2 Upper Intermediate

    describes a feeling or behavior, like a laugh or a smile, that quickly spreads to other people.

    tending to spread from person to person through social contact or emotional resonance.

    Example

    Her infectious laugh soon had everyone in the room giggling along with her.

    Example

    The team captain's infectious enthusiasm served as a catalyst for the younger players, lifting their spirits despite the early deficit in the score.
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  1. 3 exciting or memorable (adj.)
    C1 Advanced Informal

    describes something very exciting or catchy that makes people want to join in.

    evoking excitement or interest in a way that is easily picked up by an audience or group.

    Example

    The band played a song with an infectious beat that got everyone dancing.

    Example

    The marketing campaign relied on an infectious energy that resonated with younger consumers, leading to a rapid increase in brand recognition.
Origin

Borrowed from New Latin īnfectiōsus. By surface analysis, infect + -ious.

Word family

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