(1) Published after the death of the author. (2) Following or happening after one's death.
Example:
Vincent Van Gogh's rise to posthumous fame as one of the world's greatest artists came despite the fact that he scarcely sold a single painting during his lifetime.
Posthumous fame is fame that comes a little late, since the meaning of posthumous in Latin is "late born." In fact, its original meaning in English is "born after the death of the father." Bill Clinton is the posthumous son of a father who died in an automobile accident. The word is now mostly used of artistic works that appear after the death of the artist. From the poetry of Emily Dickinson to the diary of Anne Frank, posthumous works have often become legendary.