I wandered lonely as a cloud. Wordsworth was making a comparison between human loneliness and the isolation of a single cloud in the sky. A simile compares two things with the words 'as' or 'like. read more
This reminds us that the main figure of speech in this poem is less the simile than the overriding personification. The cloud is lonely, like a person. The daffodils feel “glee” and dance together like people, and so on. read more