diarrhea

n. abnormally frequent and fluid bowel movements

Diarrhea (in American English) or diarrhoea (in British English) is a condition in which the sufferer has frequent watery, loose bowel movements (from the Greek word διάρροια; literally meaning "through-flowing").  Acute infectious diarrhea is a common cause of death in developing countries (particularly among infants), accounting for 5 to 8 million deaths annually. Much of the incidence of these deaths is due to the lack of adequate safe water and lack of sewage treatment capacity; the separation of drinking water from contaminated sewage is also a major issue.
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(n.)
Alt. of Diarrhoea
  

Unusually liquid bowel movements.

Frequent and watery bowel movements.