alarmalarmalarmsalarmedalarming1noun1(no plural) a sudden feeling of fear: He heard a noise, and jumped out of bed in alarm.2(pluralalarms) something that tells you about danger, for example by making a loud noise: Does your car have an alarm?a burglar alarma fire alarm3 = alarm clockLook also at false alarm.alarmalarmalarmsalarmedalarming2verb (alarms, alarming, alarmed)to make somebody or something feel suddenly frightened or worried: The noise alarmed the bird and it flew away.She was alarmed to hear that Peter was ill.