The Collaborative International Dictionary
Implacableness
Implacableness \Im*pla"ca*ble*ness\, n. The quality of being implacable; implacability.
Wiktionary
implacableness
n. The quality of being implacable.
Usage examples of "implacableness".
Most men felt that there was a kind of implacableness about the Eternal Man - a willingness to sacrifice anything in his single-minded drive toward a goal so obscure that no one else could ever fully understand it.
This might even be the first step toward a reconciliation between his Imperial Implacableness and me.