Rough wind, that moanest loud
Grief too sad for song;
Wild wind, when sullen cloud
Knells all the night long;
Sad storm whose tears are vain,
Bare woods, whose branches strain,
Deep caves and dreary main,--
Wail, for the world’s wrong!
Found this Shelley poem, and I was wondering what "moanest loud" meant. Why is loud used as a noun? Is this a figure a speech?