Abandon someone to danger, as in The squadron withdrew and just let us hang out to dry. This expression alludes to hanging wet laundry on a clothesline. [Slang; 1960s]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.