Word
infectious
Phoneticsin·fec·tious, stress on the second syllable
US/ˌɪnˈfɛkʃəs/
UK/ɪnfˈɛkʃəs/
Definitions
01medical/disease
B2 · Upper Intermediate Medicine Technical
adj. describes a disease that can be passed from one person to another through germs or viruses.
adj. relating to a disease caused by a pathogen that enters the body and is capable of being transmitted to other hosts.
“The doctor warned that the flu is highly infectious during the first few days.”
“Public health officials monitored the outbreak closely, concerned by how infectious the new strain appeared to be in densely populated urban areas.”
Synonyms
Antonyms
02spreading feelings
B2 · Upper Intermediate
adj. describes a feeling or behavior, like a laugh or a smile, that quickly spreads to other people.
adj. tending to spread from person to person through social contact or emotional resonance.
“Her infectious laugh soon had everyone in the room giggling along with her.”
“The team captain's infectious enthusiasm served as a catalyst for the younger players, lifting their spirits despite the early deficit in the score.”
Synonyms
03exciting or memorable
C1 · Advanced Informal
adj. describes something very exciting or catchy that makes people want to join in.
adj. evoking excitement or interest in a way that is easily picked up by an audience or group.
“The band played a song with an infectious beat that got everyone dancing.”
“The marketing campaign relied on an infectious energy that resonated with younger consumers, leading to a rapid increase in brand recognition.”
Synonyms
Antonyms
Collocations
Common phrases and expressions where native English speakers use the word “infectious” in context.
Real-World Examples
“They’re clearly over the moon – and it’s infectious.” “As an infectious disease epidemiologist , I study the reasons for changes in population health risks around the world.” Etymology
Borrowed from New Latin īnfectiōsus. By surface analysis, infect + -ious.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.
Word family
VERB
NOUN
ADJECTIVE
- Exam level
- CambridgeCambridgeCambridge English QualificationsThe exam suite from Cambridge University Press & Assessment, from A1 Movers up to C2 Proficiency. The benchmark names double as CEFR labels.B2 FirstIELTSIELTSInternational English Language Testing SystemThe 0–9 band test co-owned by the British Council, IDP, and Cambridge. Used for university entry, work, and migration.5.5–6.5TOEFL iBTTOEFL iBTTest of English as a Foreign Language, Internet-Based TestETS's academic English test, the standard route for US university admissions. Scored 0–120, with a 1–6 scale since 2026.1–6 scale: 4.0–4.572–94TOEICTOEICTest of English for International CommunicationETS's workplace English test, big in Japan and Korea. Listening & Reading scores 10–990 and tops out at C1.785–944
- Frequency
- Frequent
- Level
- B2 · Upper Intermediate
- Updated
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