choppiness
roughness
rough water

It comes as a bit of a shock, then, to see the relationship hit rough waters within a few years.

The difference is that we have rough here and more water.

The wall ran all the way into rough water on both sides.

But Grant didn't seem to care about the rough water.

"The rough water helped us, but we had to row the race of our lives."

For a quarter of an hour they were in rough water.

The end result would not offer much peace of mind in rough water.

We rose higher above the rough water and headed north into the night.

It is well known for its swiftly developing rough water.

I came thus into rough water and the dark, out on the open Gulf.