bateless

From bate +‎ -less.

bateless (comparative more bateless, superlative most bateless)

1. (obsolete) Not to be abated or subdued; impossible to blunt, curtail, or reduce to anything other than full strength or intensity.
   • 1594, William Shakespeare, The Rape of Lucrece, lines 8–9:

     Haply the name of chaste unhapp'ly set / This bateless edge on his keen appetite,

• See Thesaurus:immutable or Thesaurus:relentless

• beatless, besteals, betassel