Wiktionary
vb. 1 (context intransitive euphemistic UK English) To pass gas; to break wind. 2 (context transitive English) To vent, usually, to reduce pressure in a container. 3 (context intransitive English) To let steam escape through a passage provided for the purpose. 4 (context idiomatic English) to shirk or disregard (a duty or person). 5 (context transitive English) To forcibly disconnect something by use of a firearm or explosive device.
WordNet
v. come off due to an explosion or other strong force
Usage examples of "blow off".
As it happens, I didn't actually see my bullet blow off the back of his skull, and sometimes it's hard to believe in my gut that I really did it—.
Under the circumstances I'd tell any agent to blow off the contact, much less contact with Megan.
Those who hope that the Negro needed to blow off steam and will now be content will have a rude awakening if the nation returns to business as usual.
No one would have figured Kid Stealth would blow off his own legs to escape that little death trap, but he did and survived.
Give me any shit and I'll blow off your arms and legs, cut off your nose and feed it to you.
He rang blow after blow off of Edmund's shield, careful not to snap the blade on the boss or the metal-rimmed edge.