contagious (adj.)
spreading by contact
Examples
- Flu is contagious.
Key rules
- Contagious means spreading by contact or air
- A contagious disease, a contagious illness
- Contagion is the noun
Common mistakes
- Flu is contagion → Flu is contagious
- The disease is contagiously → The disease is contagious
Use cases
- Health warnings
- Describing illnesses
- Hygiene advice
💡 Tip: Contagious describes a disease that spreads; infectious is similar and more formal.