alarm alarm /əˈlɑrm/

noun

1. () Fear resulting from the awareness of danger  ( consternation , dismay , alarm )
   fear resulting from the awareness of danger
     There was consternation among the employees when they learned about the sudden layoffs.
   There was consternation among the employees when they learned about the sudden layoffs.
   
2. () A device that signals the occurrence of some undesirable event  ( alarm system , warning device , alarm )
   a device that signals the occurrence of some undesirable event
    The alarm went off when he tried to open the door without the key.
   The alarm went off when he tried to open the door without the key.
   
   
3. A clock that wakes a sleeper at some preset time  ( alarm , alarm clock )
   a clock that wakes a sleeper at some preset time
    I set my alarm for 6 am to wake up for work
   I set my alarm for 6 am to wake up for work
   
   
4. An automatic signal (usually a sound) warning of danger  ( alarm , alarum [Archaic] , alert , warning signal )
   an automatic signal (usually a sound) warning of danger
   

verb

1. () Fill with apprehension or alarm; cause to be unpleasantly surprised  ( appal [Canadian, British] , appall [American] , dismay , alarm , horrify )
   fill with apprehension or alarm; cause to be unpleasantly surprised
    I was horrified at the thought of being late for my interview
   I was horrified at the thought of being late for my interview
    The news of the executions horrified us
   The news of the executions horrified us
   
2. () Warn or arouse to a sense of danger or call to a state of preparedness  ( alarm , alert )
   warn or arouse to a sense of danger or call to a state of preparedness
    The empty house alarmed him
   The empty house alarmed him
    We alerted the new neighbors to the high rate of burglaries
   We alerted the new neighbors to the high rate of burglaries