have recourse to or make an appeal or request for help or information to; "She called on her Representative to help her"; "She turned to her relatives for help"
a device that signals the occurrence of some undesirable event
an automatic signal (usually a sound) warning of danger
fear resulting from the awareness of danger
warn or arouse to a sense of danger or call to a state of preparedness; "The empty house alarmed him"; "We alerted the new neighbors to the high rate of burglaries"
an informant who exposes wrongdoing within an organization in the hope of stopping it; "the law gives little protection to whistleblowers who feel the public has a right to know what is going on"; "the whistleblower was fired for exposing the conditions in mental hospitals"