1. not working properly or not able to perform its intended purpose
2. serving no practical purpose; purely decorative or ornamental

Examples

• The old printer is completely nonfunctional and needs to be replaced.
• After the storm, several streetlights became nonfunctional.
• The buttons on his jacket are purely nonfunctional decorations.
• The nonfunctional fireplace serves only as a design element.
• Her phone became nonfunctional after she dropped it in water.
• The museum displayed several nonfunctional replicas of ancient tools.
• The nonfunctional elevator forced everyone to use the stairs.