old-fashioned Something or someone is aged, obsolete, or outdated. The phrase comes from the opening line of the folk song "Old Gray Mare." Its (rare) modern use is usually somewhat derogatory. Man, that's a terrible sound coming from my car. I guess the old gray mare ain't what she used to be. A: "What happened, Mom? You used to be a great dancer." B: "Well, the old gray mare ain't what she used to be!"