Lacking scruples or principles
Without pity; said of persons
Showing little evidence of pity; said of actions, policies, etc.
He could be ruthless, but was not habitually cruel.
The "ablest and most ruthless of the Angevins," as J.
Qatwali was as ruthless in battle as he was.
The Goths showed themselves not absolutely ruthless conquerors.
The way they secure their positions is through the ruthless application of violence.