From Longman Dictionary of Contemporary Englishfire something ↔ off phrasal verb1 SHOOTto shoot a bullet, bomb etc into the air Chuck reloaded and fired off both barrels. Mexicans have a tradition of firing off guns to welcome in the new year.2 SENDto quickly send an angry letter to someone I fired off a furious letter to the editor. → fire→ See Verb table
Examples from the Corpus
fire off• Behind them stood a line of Mukhabarat men, with orders to shoot anyone who failed to fire or aimed off.• It shouldn't have happened.Anger over the chemical fire that closed off a town.• Neither resisted, but the man suddenly opened fire before driving off empty-handed.• They agreed they were quite lucky to escape the fire and set off for a foreign country.• The speed the fire had taken off had been astonishing.• Leyland fired one off the bar, and the police threw him in jail overnight.• They returned fire before breaking off the engagement.• Then he could fire the troublemakers off the mountain.