SYN: Yield, relax, soften.
ANT: Persist, harden.
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KEY: Relentless.
SYN: Cruel, inexorable, unyielding, remorseless, unmerciful, truculent.
ANT: Yielding, humane, feeling, clement, merciful, compassionate.
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KEY: Relevancy, [See RELEVANT].
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KEY: Relevant.