use your head for more than a hatrack

use (one's) head for more than (just) a hat rack

To think in an intelligent, logical, or clever manner; to not think or act like a fool. (I.e., to make use of the brain in one's head, rather than just using the head as a place to hang a hat.) There isn't a simple answer, so you'll have to use your head for more than a hat rack to find the best solution. Come on, Tom, that was a really silly error. You need to start using your head for more than just a hat rack.
See also: hat, head, more, rack, use
Farlex Dictionary of Idioms.

use your head for more than a hatrack

 and use your head for more than something to keep your ears apart
Rur. to think. How are we going to solve this problem? Come on, use your head for more than a hatrack. Instead of whining about it, why don't you use your head for more than something to keep your ears apart?
See also: hatrack, head, more, use
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • use (one's) head for more than (just) a hat rack
  • use (one's) head for more than something to keep (one's) ears apart
  • (someone) thinks (they) are so smart
  • never in a month of Sundays
  • go against the flow
  • never in a million years
  • What are you on?
  • think out of the box
  • What color is the sun in your world?
  • think back