A person. For example, Every living soul in this town has a stake in the decision to ban smoking, or The place was empty—not a living soul to be found. [First half of 1600s]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.