1. to work together with others on a project or activity
2. to help an enemy who has invaded your country
Usage: often considered treasonous

Examples

• The scientists collaborated on groundbreaking research.
• We need to collaborate more effectively as a team.
• The two companies collaborated to develop new technology.
• Students were asked to collaborate on the group project.
• The artists collaborated to create a beautiful mural.
• During the war, some citizens collaborated with the occupying forces.