1. a person who works together with others toward a common goal or purpose
2. a person who is willing to cooperate or comply with requests or instructions

Examples

• The two scientists were excellent cooperators on the research project.
• She proved to be a willing cooperator in the community cleanup effort.
• Good cooperators are essential for any team to succeed.
• The cooperators met weekly to discuss their shared objectives.
• He was known as a reliable cooperator who always followed through on commitments.
• The organization sought cooperators who shared its mission and values.