Definitions of fearful:

• adjective:   experiencing or showing fear

  Example: "A fearful glance"

• adjective:   timid by nature or revealing timidity

  Example: "Cast fearful glances at the large dog"

• adjective:   extremely distressing

  Example: "Fearful slum conditions"

• adjective:   lacking courage; ignobly timid and faint-hearted
• adjective:   causing fear or dread or terror

  Example: "A fearful howling"