Final answer:
In the poem excerpt, the speaker compares their solitude to a cloud, using a simile to emphasize the feeling of isolation and freedom.
Step-by-step explanation:
In the given excerpt from "I wandered lonely as a cloud" by William Wordsworth, the speaker compares their state of solitude to a cloud. This is a clear example of a simile, where the speaker's emotional state of being alone is likened to a cloud floating above valleys and hills. It emphasizes the sense of isolation as well as the ability to wander freely and aimlessly, much like a cloud moves across the sky.