Zoilus, a Greek rhetorician who flourished in the 3rd century B.C.; was distinguished for the bitterness with which he criticised Homer, and whose name has in consequence become a synonym for a malignant critic, hence the saying, “Every great poet has his Zoilus.”
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Zohar * Zola, Émile