alarm

[1]	frighten , scare , daunt , startle , terrify , panic , unnerve , dismay , disturb , upset
[2]	appal , appall , horrify
[3]	alert

[1]	warning , alert , danger-/distress-signal , tocsin , bell , gong , siren , whistle , horn
[2]	fear , warning device , alarm system , fright , apprehension , dismay , trepidation , terror , dread , anxiety , excitement , panic , consternation , distress , nervousness , uneasiness , discomfort
[3]	warning signal , alarum
[4]	alarm clock