contagious

contagious — adjective

1. describes a disease that passes from one person to another through touch, coughi

1.adjectiveB1
Definition

describes a disease that passes from one person to another through touch, coughing, sneezing, or contact with a surface that an infected person has used.

Example

Élise stayed home from school because her cold was highly contagious.

be + highly contagious (intensifier pattern)

The nurse warned us that flu viruses are especially contagious in closed rooms.

Common collocations
  • contagious disease
  • contagious virus
  • highly contagious
  • contagious illness
  • contagious infection
Synonyms
  • infectious

    broader term — covers all pathogen-caused diseases, including those that spread through air, water, or food, not just contact

  • communicable

    more formal; used in public-health contexts about diseases that can be passed between hosts

  • transmissible

    most technical; can apply to diseases, genes, or traits passed from one organism to another

  • catching

    informal, conversational — 'Is it catching?' is a common everyday question

Antonyms

Grammar Patterns

contagious + noun (disease, virus, illness)

be + contagious

remain/stay + contagious

Usage Note

Contagious refers specifically to diseases that spread through physical contact or close proximity. It is narrower than 'infectious' — all contagious diseases are infectious, but not all infectious diseases are contagious (e.g. tetanus is infectious but cannot spread between people).

Common Mistakes

He is contagious with the flu.
He has the flu and is contagious.
'Contagious' describes the person's state directly; it is not followed by 'with' + disease.

2. describes a person who has a sickness that others nearby may pick up through tou

2.adjectiveB2
Definition

describes a person who has a sickness that others nearby may pick up through touch or close contact.

Example

Folake was told she would stay contagious for a week after the fever went away.

stay + contagious (linking verb)

The daycare asked parents to keep contagious children at home until they recover.

attributive: contagious + noun (children)

Common collocations
  • contagious person
  • contagious patient
  • remain contagious
  • still contagious
  • contagious child
Synonyms
  • infectious

    can also describe a person carrying a disease, though 'contagious' is preferred for contact-spread

  • sick

    much broader and less precise; a sick person may or may not be contagious

Antonyms

Grammar Patterns

be + contagious

remain/stay + contagious

still + contagious

Usage Note

This sense is almost always used predicatively (after 'be,' 'remain,' 'stay'). When used attributively before a noun, it typically modifies 'person,' 'patient,' or 'child' — e.g. 'contagious patients.'

Common Mistakes

The contagious man went to the party.
The man went to the party while he was still contagious.
Attributive use without specifying when or why sounds unnatural in most contexts; predicative use clarifies the temporary state.

3. describes a feeling or way of behaving that passes rapidly between people, causi

3.adjectiveB1
Definition

describes a feeling or way of behaving that passes rapidly between people, causing others to share the same emotion or action.

Example

Jisoo's laughter was so contagious that soon the whole room was giggling.

be + contagious describing an emotion

The choir sang with contagious energy, and the audience began clapping along.

attributive: contagious + noun (energy)

Common collocations
  • contagious laughter
  • contagious enthusiasm
  • contagious smile
  • contagious mood
  • contagious energy
Synonyms
  • infectious

    used almost interchangeably in this figurative sense, though 'contagious' is slightly more common for emotions

  • spreading

    describes the action directly but lacks the vivid metaphor of 'contagious'

  • catching

    informal — 'Her excitement is catching' means the same thing in casual speech

Grammar Patterns

contagious + noun (laughter, enthusiasm, smile)

be + contagious

prove + contagious

Usage Note

This figurative sense is very common in everyday English. It typically describes positive emotions (laughter, enthusiasm, joy, excitement) but can also apply to negative moods such as panic or fear. The literal medical sense does not apply.

Common Mistakes

His happiness is very contagious to people.
His happiness is very contagious.
No preposition follows 'contagious'; it does not take 'to' + person.

Word family

  • contagion
    nounC1
  • contagiously
    adverbC2
  • contagiousness
    nounC2
  • non-contagious
    adjectiveC1

Synonym discussion

Sense: adjective/1

All four words describe diseases that can spread between people, but each has a different emphasis. 'Contagious' stresses transmission through direct contact, shared surfaces, or close proximity — it is the most common word in everyday medical talk. 'Infectious' is broader, covering any disease caused by a pathogen (bacteria, virus, fungus) regardless of the transmission route; tetanus is infectious but not contagious. 'Communicable' is more formal and is used in public-health language about diseases that can be passed between hosts. 'Transmissible' is the most technical option, used for diseases, genetic traits, or information that can be passed from one carrier to another. In everyday conversation, most speakers use 'contagious' for colds and flu, and 'infectious' when talking about more serious illnesses.

infectious ↗communicabletransmissiblecatching ↗

Common collocations

Adverbs

Etymology

LatinFrenchEnglish

From Latin 'contagiosus,' meaning 'touching' or 'contact,' from 'contagio' (contact, infection), which combines 'con-' (together) and 'tangere' (to touch). The word entered English around the 14th century, first used for diseases that spread through physical contact, then later extended in the 19th century to describe emotions and behaviours that 'spread' among people like an illness.