alarum

1. (normally archaic) A danger signal or warning.Examples: "These are the only visible luxuries: the rest is the irreducible minimum of poverty's needs: a wretched bed heaped with all sorts of coverings that have any warmth in them, a draped packing case with a basin and jug on it and a little looking glass over it, a chair and table, the refuse of some suburban kitchen, and an American alarum clock on the shelf above the unused fireplace: the whole lighted with a gas lamp with a penny in the slot meter."; "The story struck the depressingly familiar note with which true stories ring in the tried ears of experienced policemen.[…]The second note, the high alarum, not so familiar and always important since it indicates the paramount sin in Man's private calendar, took most of them by surprise although they had been well prepared."; "Just another forum, then, sounding the usual alarums on the looming threat from global warming?"