My co-workers and I have odd conversations on a daily basis and today our conversation was about the phrase "They went missing" in reference to a person or group of persons missing. We do not believe it sounds correct. At any rate, I'm very bothered by the fact that I majored in English and can define what "They" and "went" in the sentence are (noun, verb) but for the life of me I cannot define what "missing" would be. Can anyone out there help? Thanks!