1. in a manner that spreads from person to person by direct or indirect contact; transmissibly
Usage: often used in medical or health contexts
2. in a manner that spreads readily from one person to another; in a way that is easily caught or adopted by others
Usage: figurative use; often describes emotions, attitudes, or behaviors

Examples

• The patient was contagiously ill and had to remain isolated.
• Her enthusiasm spread contagiously throughout the team.
• The disease spreads contagiously in crowded environments.
• He laughed contagiously, and soon everyone in the room was laughing too.
• The virus transmitted contagiously during the winter months.
• Her optimism was contagiously uplifting to those around her.