Given the patient's history of chronic liver disease, and the acute hematemesis (vomiting of blood) without previous history of vomiting, the most likely diagnosis is esophageal varices.
Esophageal varices are enlarged veins in the esophagus, which can cause bleeding if they puncture or tear. The patient's history of chronic liver disease, distended abdomen without rebound, guarding or organomegaly, and the presence of a fluid wave on physical examination would all point towards this diagnosis.
Mallory-Weiss tear, arteriovenous malformation, and perforated duodenal ulcer are not likely to be the cause of this patient's symptoms.