Sin

грех is well established, including in secular Russian idiom, but seven decades of state atheism have partly flattened it into a folk-moral or even joking register (‘грех жаловаться’ = ‘it’d be a sin/shame to complain’), and secular readers may hear it as outdated moralism rather than a serious category of guilt before a personal God. Romans 1:18-3:20’s weight must be restored explicitly, not assumed from the word alone.