New King James Version
undiscerning, untrustworthy, unloving, unforgiving, unmerciful;

King James Bible
Without understanding, covenantbreakers, without natural affection, implacable, unmerciful:

American Standard Version
without understanding, covenant-breakers, without natural affection, unmerciful:

Berean Study Bible
They are senseless, faithless, heartless, merciless.

Douay-Rheims Bible
Foolish, dissolute, without affection, without fidelity, without mercy.

English Revised Version
without understanding, covenant-breakers, without natural affection, unmerciful:

World English Bible
without understanding, covenant breakers, without natural affection, unforgiving, unmerciful;

Young's Literal Translation
unintelligent, faithless, without natural affection, implacable, unmerciful;

Romans 1:31 Additional Translations ...