What does "high sea" mean?

The sea when it is very rough due to strong winds and storms, such that the sea encroaches much further inland than is normal, often causing damage.

What is a synonym for "high sea"?

Common synonyms include: deep, drink, high seas, hydrosphere, main, ocean depths.

noun

noun ·Rare ·Advanced level

Noun

1
The sea when it is very rough due to strong winds and storms, such that the sea encroaches much further inland than is normal, often causing damage.
"The ship eventually broke in half in high sea and winds."
2
Alternative form of high seas (“open ocean”). alt-of, alternative, uncountable

"The ship eventually broke in half in high sea and winds."

From Middle English hey see, hey se, from Old English hēahsǣ (“the high sea, the deep”), equivalent to high + sea.