A spasm of the diaphragm resulting in a rapid, involuntary inhalation that is stopped by the sudden closure of the glottis and accompanied by a sharp, distinctive sound. An attack of these spasms. Often used with the. The sound made by such a spasm or a sound resembling it: "the urgent hiccup of a police siren\u201d ( John Updike). To make a hiccup or a sound like a hiccup. To have an attack of hiccups.