Answer: herculean

AnswerCrossword Clue
HERCULEANRequiring superhuman effort
HERCULEANOf a famous Greek hero.
HERCULEANDescribing U. N.'s task.
HERCULEANFormidable, as a task
HERCULEANAlmost impossible, as a task
herculean(of a person) Muscular and strong
herculeanof extraordinary strength and size
herculeanRequiring great strength or effort