alarmer means one who alarms; one who sounds the alarm. Lexicurio rates it Sui generis — a strength score of 87 out of 100.
Etymology
From alarm + -er (agent noun suffix) or -er (measurement suffix).
noun
- One who alarms; one who sounds the alarm.
- A multialarm fire of a specified number of alarms.“This three-alarmer brought out no fewer than seven steam pumpers, which are drawing water from a fire cistern...”