Idioms and Phrases with sporting blood
Willingness to take risks, as in His sporting blood won't let him stay away from the races. This idiom uses sporting in the sense of “associated with gambling.”
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.