half a mind
An inclination that is not definite or resolute. For example, I've half a mind to drop the course, or He went out with half a mind to walk all the way there. [First half of 1700s] Also see have a good mind to.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.