To show extreme anger, frustration, or grief. In ancient times it was customary to show grief by literally pulling at one’s hair. The practice was referred to by Homer in the Iliad, with reference to Agamemnon, and appears in other ancient writings. Shakespeare used it in Troilus and Cressida (4.2), “Tear my bright hair, and scratch my praised cheeks,” and Thackeray in The Rose and the Ring (1855), “Tearing her hair, crying and bemoaning herself.” Today we are more apt to use it for anger or vexation, and entirely figuratively.