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.
Farlex Dictionary of Idioms. © 2022 Farlex, Inc, all rights reserved.
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.
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.