1. A state of readiness to respond
   "alerting was indicated by the desynchronization of the EEG";
   - alertness
    
2. A warning that serves to make you aware of danger
   "The system's alerting of potential security breaches saved the company";
   - alert

1. Warn or arouse to a sense of danger or call to a state of preparedness
   "We alerted the new neighbours to the high rate of burglaries";
   - alarm

Type of: arousal, warn, warning

Encyclopedia: Alerting