Flowing or surging floodwaters; a moving deluge of water; a tempestuous sea.

A heavy sea in which large waves rise and dash upon the coast without apparent cause.

With an epithet indicating the roughness or smoothness of the waves, the presence or absence of swell, etc. Hence without qualification = a heavy…

A rough sea. Usually in a seaway (said of a ship).

‘high turbulent waves with little wind’ (Smyth Sailor's Word-bk.).