It's Merriam-Webster's Word of the Day for January 12th.
Today's word is brackish, spelled B-R-A-C-K-I-S-H.
Brackish is an adjective.
It means somewhat salty, usually describing water or bodies of water,
such as rivers, lakes, and estuaries.
The word can also mean not appealing to the taste or repulsive.
Here's the word used in a sentence from Wired.
The blood testing organs don't measure water levels, but rather the concentration of salt,
whose healthy range lies at almost exactly the same concentration as that of the brackish intertidal water in which vertebrates first evolved,
which is about one-third as salty as seawater.
When the word brackish first appeared in English in the 1500s,
it simply meant salty, as did its Dutch parent, Braak.
Then as now, brackish was used to describe water that was a mixture of saltwater and freshwater,
such as one encounters when 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 stinky-ish
if you prefer not just salty qualities of coastal estuaries and swamps.