WordWeb Online

1. Experiencing a sudden sense of danger

1. Fill with apprehension or alarm; cause to be unpleasantly surprised
   "I was alarmed at the thought of being late for my interview"
   - dismay, appal [Brit, Cdn], appall [US], horrify
    
2. Warn or arouse to a sense of danger or call to a state of preparedness
   "The empty house alarmed him"
   - alert

See also: afraid, alarmist, 'fraid [non-standard]

Type of: affright, fright, frighten, scare, warn

Encyclopedia: Alarm