Originally describing sharp, pungent taste—bitter herbs, salt water as opposed to sweet. James uses it metaphorically for moral and spiritual realities. Can both fresh and bitter water flow from the same spring (Jas 3:11)? No—and neither should blessing and cursing flow from the same mouth. Bitter jealousy and selfish ambition (Jas 3:14) poison the heart like bitter water poisons a well. The physical sensation of bitterness becomes a picture of corrupted character—harsh, sharp, unpleasant, spoiling what should be pure.