1. to give someone facts or information about something
2. to give someone official notice or warning
Usage: formal
3. to give information to authorities about someone’s wrongdoing
Usage: often followed by ‘on’ or ‘against’

Examples

• Please inform me when the meeting starts.
• The teacher informed the students about the test schedule.
• We regret to inform you that your application was not accepted.
• The police informed the family of the accident.
• He decided to inform on his criminal associates.
• The witness informed against the suspect.
• I’ll inform you of any changes to the plan.