1. people who watch or notice something carefully
Usage: plural of observer
2. people who attend meetings or events to watch but not participate
Usage: formal contexts
3. people who study or monitor situations professionally
Usage: professional or academic contexts

Examples

• The election observers reported no irregularities at the polling stations.
• Wildlife observers spotted several rare birds in the nature preserve.
• International observers were invited to monitor the peace negotiations.
• The researchers acted as neutral observers during the experiment.
• Political observers predicted a close race between the candidates.
• The meeting was open to observers from the community.
• Military observers were stationed along the border to watch for violations.