May not be stagnant, but could be called a Mortlake or an Oxbow lake
Oxbow lake
billabong
Unlike rushing water in a river, water in a pond is stationary and stagnant. 1 stagnant water or air is not moving and therefore smells unpleasant: Few fish survive in the stagnant waters of the lake. 2 not developing, growing or changing: The new investments are aimed at reviving the stagnant economy. The housing market has been largely stagnant over the past few months.
A buyou is another term for a bayou - a slow-moving, often stagnant creek or river.
Do not refill your canteen from stagnant water. I left the company because my career became stagnant.
A stagnant swamp is often referred to as a "dead swamp" or simply a "stagnant marshland."
The answer to that is varicose veins.
Stagflation was an economic condition in which unemployment was high, the economy was stagnant, but prices were rising (inflation).
Active, energetic, and dynamic are a few antonyms of stagnant.
The answer is a caldera lake.
The stagnant water smelled nasty.