1. To shoot or launch some ballistic projectile, such as a bullet or a missile, especially in a haphazard or careless manner. A noun or pronoun can be used between "shoot" and "off." The criminal shot off several rounds into the air to show the criminals he meant business. The country has been accused of intentionally shooting off test rockets over the sovereign airspace of its neighbor to the north, in direct conflict of their peace treaty.

2. To cause something to be severed (from something else) as a result of being shot with a projectile of some kind. A noun or pronoun can be used between "shoot" and "off." The man accidentally shot off his thumb with the pistol he was holding because he didn't realize the safety was off. He can shoot the leaf off a tree from fifty feet away with a bow and arrow.

3. To send some written message very quickly or casually. A noun or pronoun can be used between "shoot" and "off." Would you mind shooting off an email to the accountant to see when our tax refund is due? I shot a message off to my mother about next weekend, but she hasn't gotten back to me yet.