Definitions:

1. to fill with apprehension or alarm verb
   • I don't mean to alarm you, but your car is on fire.
2. to warn or arouse to a sense of danger, or to call to a state of preparedness verb
   • The empty house alarmed me.

Synonyms:

• alarm clock
• alarm system
• alert
• appall
• consternation
• dismay
• horrify
• warning device

NearBy Words:

• alarmed
• alarming
• alarmingly
• alarmism
• alarmist