the GNU version of the Collaborative International Dictionary of English
adj. Unmoved by appeals for sympathy or forgiveness; insensible to the distresses of others; destitute of tenderness; unrelenting; unyielding; unpitying.
The Century Dictionary and Cyclopedia
Incapable of relenting; unmoved by pity; unpitying; insensible to the distress of others; destitute of tenderness.
Synonyms Implacable, etc. See inexorable, and list under unrelenting.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. not to be placated or appeased or moved by entreaty
adj. never-ceasing
Word Usage
"This is what I call the relentless rules of humble arithmetic from Justice Brandeis."