harm a hair on (one's) head(redirected from harmed a hair on their heads)
harm a hair on (one's) head
To hurt or injure one in any way. This phrase is often used in the negative. If I find that he harmed a hair on your head, I'll go to his house right now! He wouldn't dare harm a hair on your head—not when I'm around.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.