The Hebrew zakh (H2134) means pure, clean, or innocent โ especially in a transparent, unmixed sense. Job uses it to declare his own innocence: 'My prayer is pure (zakh)' (Job 16:17). In Proverbs 20:11, 'Even small children are known by their actions, so is their conduct really pure (zakh) and upright?' The word carries the sense of something unmixed, like clear water or transparent light.
Zakh appears in Job's extended legal argument before God, where he insists on his innocence despite his suffering. The word is related to zakah (to be clean/pure) and zakok (transparent). Theologically, true purity before God is not achieved by human effort but is the result of divine cleansing and imputed righteousness. The NT echo is 'Blessed are the pure in heart' (Matthew 5:8) โ those whose inner life is single, unmixed, and transparent before God, they alone see Him.