1. to cause disease in a person, animal, or plant by introducing harmful microorganisms
2. to spread harmful ideas, feelings, or attitudes to others
Usage: figurative
3. to contaminate something with harmful microorganisms

Examples

• The virus can infect anyone who comes into contact with it.
• Poor hygiene practices may infect the wound.
• His negative attitude began to infect the entire team.
• Bacteria from raw meat can infect other foods if not handled properly.
• The computer virus will infect any system it contacts.
• Her enthusiasm seemed to infect everyone around her.
• Dirty water can infect people with serious diseases.