Hiccups, also known as singultus and hiccoughs, are involuntary and random spasms of the diaphragm, which results in the closing of the vocal cords, according to Healthline and WebMD. Hiccups can be irritating and embarrassing but usually last a few minutes to a few days. In rare occasions hiccups last a few weeks to years. Prolonged hiccups that last more than a few hours are severe. Hiccups can also be a symptom of something serious.