An alarmer is someone who has an alarm that has gone off accidentally. Like a car-alarm or a house alarm. An alarmer who hasn't switched off their alarm is the worst kind. This is when the alarm just stays on continuously and you have to go somewhere else before it drives you crazy.
Wonder when that alarm will stop going-off like that!! oh, looks like it will be soon, I think that's the alarmer coming over.
by Professor of new English June 22, 2005