The word fear, in English, comes from a Greek word. It is abstract in nature and context. It is a feeling, albeit an awful feeling, but there is no action involved. That is not the case in the Hebrew word yirah.
When a Hebrew speaker considers yirah, fear, what comes to his mind is the feeling of ‘flowing in the gut’. This is quite a concrete understanding and, to me, carries with it both the feeling of terror and the feeling of reverence.