Poet's inspiration can be found in the crossword solutions of ERATO (5 letters) and MUSE (4 letters). ERATO is the Greek goddess of lyric poetry, love, and music. She is one of the nine Muses, who were the inspirational goddesses of literature, science, and the arts in Greek mythology. MUSE is another name for the nine Muses, and they are often seen as a source of inspiration for poets. Therefore, ERATO and MUSE are both appropriate answers to the clue 'POET's Inspiration'.