Wiktionary
n. (context nautical English) A large quanity of water on a ship's deck as a result of massive waves during a large storm. Often damaging equipment and global ship response.
Usage examples of "green water".
Ryder would not have cared to transfer twenty-odd Sea Fencibles from a sinking turtleback with the waves sending green water over the cockpit forward.
It pierced the morning air, then the blue-green water of the Lake of Death.
The skylight overhead was a long bronze crack in the dark roof, and morning light filled the giant cylindrical chamber with the kind of photon rain she had been craving all winter, brown light everywhere, the bamboo and pine and cypress rising over the tile rooftops and blazing like green water.
Rik said from where he stood, trying to see something besides pretty green water.
At least two acres of green wonder spread before him, a blaze of flowers, trees where gorgeously colored birds fluttered and trilled, a wide, deep pool of green, green water, and over all, the glory of brilliant sunshine.