Leave, as in When I inquired about his sister, he turned on his heel and walked away. This idiom alludes to making a sharp about-face similar to a military step but here usually implies a sudden departure. It was first recorded in 1751.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.