Bible Dictionary
TERRIBLE, TERROR
Terrible or terror describes whatever inspires dread because of greatness, power, cruelty, holiness, or judgment. God is terrible in His majesty and justice, while enemies and persecuting powers may also be described as terrifying; reverent fear before Christ includes awareness that He is Judge.
Biblical Usage
God is called terrible because of his awful greatness, infinite power, inscrutable dealings, perfect holiness, covenant faithfulness, strict justice, and judgments. Enemies of God and his people may also be terrible. “The terror of the Lord” refers to reverent fear arising from the knowledge that Christ is Judge.