Let's break it down:
* Grim: This word suggests the raven's dark and foreboding appearance. It evokes a sense of gloom and solemnity.
* Ancient: This word implies the raven is old, perhaps even wise, and has witnessed many things, adding to its aura of mystery and knowledge.
* Wandering from the nightly: This phrase emphasizes the raven's nocturnal nature and its connection to the darkness. It also suggests the raven is a creature of the shadows, appearing suddenly and unexpectedly.
Together, these words create a vivid image of a brooding, sinister raven, a creature that is both intriguing and unsettling. The raven's arrival in the poem, "wandering from the nightly," is a symbolic moment, marking the beginning of the narrator's descent into despair and madness.
This phrase is significant because it sets the tone for the entire poem. It foreshadows the darkness and sorrow that will follow, creating a sense of dread and anticipation in the reader. The raven itself becomes a symbol of the narrator's grief and obsession, and its ominous presence serves to deepen the poem's overall mood of gothic horror.