use (one's) head

use (one's) head

To use one's own intelligence and intellectual ability; to think logically and rationally. In this phrase, "head" refers to one's brain. Often said as an imperative. Come on, Dean, I know you can figure this out on your own. Use your head for a change! We'll have to use our heads if we're going to have any hope of solving this supply issue.
See also: head, use
Farlex Dictionary of Idioms.

use one's head

 and use one's noggin; use one's noodle
Fig. to use one's own intelligence. (The words noggin and noodle are slang terms for "head.") You can do better in math if you'll just use your head. Jane uses her noggin and gets things done correctly and on time. Yes, she sure knows how to use her noodle.
See also: head, use
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

use one's head

Think, have common sense, as in Use your head, Martin. No one's coming out in this weather. This idiom uses head in the sense of "brain" or "intellect," a usage dating from the late 1300s.
See also: head, use
The American Heritage® Dictionary of Idioms by Christine Ammer.

use your ˈhead

(British English also use your ˈloaf) (informal) think carefully; use your intelligence: Use your loaf! Meena can’t read English, so there’s no point in writing her a letter!In rhyming slang, loaf of bread stands for ‘head’.
See also: head, use
Farlex Partner Idioms Dictionary

Use your head!

and Use your noggin! and Use your noodle!
exclam. Think!; Think it through! You know the answer. Use your head! Use your noggin’, dogg!
See also: use
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • (from) top to toe
  • (one's) day in court
  • be on (one's) pat
  • (there's) no peace/rest for the wicked
  • at (one's) doorstep
  • at doorstep
  • (one's) jig is up
  • at will
  • at somebody's expense
  • at (one's) expense