daunting

This term describes a psychological reaction to a challenge that seems overwhelmingly large or complex. It carries a heavy sense of intimidation, where the scale of the objective creates a mental barrier of fear or hesitation before the task even begins.

While similar to intimidating, daunting specifically emphasizes the perceived difficulty of a process or goal. It is frequently used in professional or academic contexts to describe ambitious projects, steep learning curves, or grueling physical journeys.