To behave submissively or obsequiously; to plead for something (pardon, a favor, and the like). The term alludes to the old custom of removing one’s hat as a sign of respect. “A man’s hat in his hand never did him any harm,” wrote Samuel Palmer (Moral Essays on Proverbs, 1710). The custom of wearing and doffing a hat has become far less common, so the term is dying out, but it is still used in diplomatic circles.