sea wolf

any of several large, voracious, marine fishes, as the wolffish or sea bass.

a pirate.

Origin of sea wolf

Middle English word dating back to 1250–1300

His later books drew heavily from experiences and people he encountered at the bar, including the cruel captain in The Sea-Wolf.

The Bars That Made America Great |Nina Strochlic |December 28, 2014 |DAILY BEAST
He shall be advanced by a sea-wolf, whom the woods of Africa shall accompany.

Old English Chronicles |Various
The gavista's wailing cry re-echoed along the rocks; the sea-wolf's howl was heard amid the darkness.

Harper's Magazine, Vol III, June 1851 |Various
Below, the sea-wolf is described as having a head “of golden coloure.”

The Philippine Islands, 1493-1898, Volume XXXIII, 1519-1522 |Antonio Pigafetta

The first passage (v. 1599 (b)-1600) I translate literally: Then many agreed upon this (namely), that the sea-wolf had killed him.

Beowulf |Release Date: July 19, 2005 [EBook #16328]
Guillim, however (p. 271), in quoting the arms of Fennor, would seem to assert the sea-wolf and sea-dog to be one and the same.

A Complete Guide to Heraldry |Arthur Charles Fox-Davies