Understanding 'Trepidation' in Context

In the book, Max and the Mysterious Map, the protagonist finds an old, tattered map that seems to glow faintly in the moonlight. As he examines it, he notices the intricate designs that are etched into the parchment, and an odd sense of excitement fills him. Suddenly, he feels a shudder of trepidation, realizing the map may lead him to unknown dangers.

Later, while pondering over a second glance at the faded symbols, Max reflects on the significance of adventure and the longing for discovery that drives many explorers. He muses, “Adventure isn’t merely a pursuit of the unknown; it is also about understanding oneself in the face of uncertainty.” You are tasked with defining the meaning of the word trepidation in this context.