The word hadephobia is derived from two Greek words, Hades (“hell”) and phobos (“fear”). This phobia is also called Stygiophobia or Stigiophobia. After all Hell is a scary place. It will have outer darkness, intense heat from the eternal fire, gnawing of teeth, pain and suffering. See Matthew 25.
Hell is a real place and those not saved (born again) will go to hell. Hell is a place of punishment and everlasting separation from God. As a Christian we shouldn’t fear hell as we are a Child of God and will be going to Heaven with the Father. But, those lost, should fear hell.