pitiless

/ˈpɪtɪləs/
adjective
  1. Showing no pity or mercy; cruel and unfeeling.
    • The storm was pitiless, destroying everything in its path.
    • Her pitiless stare made him feel completely worthless.
    • The pitiless dictator ignored the suffering of his people.
  2. Very harsh or severe, without any compassion.
    • The teacher's pitiless grading policy discouraged many students.
    • The pitiless heat of the desert sun beat down on the travelers.
    • He faced pitiless criticism from the reviewers for his first novel.