to intercept and force to change direction: to head off the stampede
to prevent or forestall (something that is likely to happen)
to depart or set out: to head off to school
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
How to use head off in a sentence
This was done in season, on account of our ignorance of all the soundings, and we had soon got the John's head off-shore again.Afloat And Ashore | James Fenimore Cooper
Tristan smites Morold's head off,-298- but a piece of the sword remains in the skull.Richard Wagner His Life and His Dramas | W. J. Henderson
Sail was at once shortened on board the Hermione, and the ship hove to, with her head off-shore.The Rover's Secret | Harry Collingwood
But same time, while she no notion o' gitt'n' him cotch, she believe she dess djuty-bound to head-off his devilment.The Cavalier | George Washington Cable
Other Idioms and Phrases with head off
Block the progress or completion of; also, intercept. For example, They worked round the clock to head off the flu epidemic, or Try to head him off before he gets home. [First half of 1800s] This expression gave rise to head someone off at the pass, which in Western films meant “to block someone at a mountain pass.” It then became a general colloquialism for intercepting someone, as in Jim is going to the boss's office—let's head him off at the pass.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.