Portrait d'une Femme by Ezra Pound uses many different types of figure of speech.
Allusion: The title refers to Henry James' Portrait of a Lady.
Alliteration: The poem uses alliteration, especially with the letter "s", giving a sibilant effect –
Sargasso Sea, score, Strange spars
polyptoton: Uses multiple forms of the same root in "dull man, dulling"
metaphor: there are many metaphors in the poem. The dominant one is of the woman as a Sargasso Sea. Knowledge or ideas are compared with spars and wares and strange woods. An interesting idea is described as "pregnant with mandrakes". Days are described as a loom.
Apostrophe: "In the slow float of differing light and deep, No! there is nothing! " interrupts the list to address the person directly.