Final answer:
The poem 'Flush or Faunus' by Elizabeth Barrett Browning uses allusion as the figurative language by referencing Faunus, a Roman god, to enhance its imagery.
Step-by-step explanation:
The excerpt from Elizabeth Barrett Browning's poem 'Flush or Faunus' uses allusion as a type of figurative language. An allusion is when a writer references another work of literature, person, or event in their writing without explicitly mentioning it. In this case, the mention of Faunus, who is a Roman god associated with nature and forests, known for his goat-like appearance and connection to wildlife, suggests an indirect reference to mythology to enhance the meaning and imagery of the poem. The head 'as hairy as Faunus' creates a vivid image and draws a comparison without stating it directly, which would be characteristic of a metaphor.