When the word brackish first appeared in English in the 1500s, it simply meant "salty," as did its Dutch parent brak. (English speakers also adopted the synonymous brack from the same source but it gets very little use.) Then, as now, brackish was used to describe water that was a mixture of saltwater and freshwater, such as one encounters where a river meets the sea. Since that time, however, brackish has developed the additional meanings of "unpalatable" and "repulsive," presumably because of the oozy, mucky, and sometimes stinky (or stinkyish, if you prefer)—not just salty—qualities of coastal estuaries and swamps.