What is Post-Impressionism?

Answer 1

Post-Impressionism started out in the 1910 by the art critic Roger Fry when he was starting an exhibition in the Grafton Gallery. Post impressionism is a famous art movement which followed quickly after Impressionism.

Answer 2

It is a term which is mainly used about Vincent Van Gogh and Paul Gauguin, even though they do not have much in common. They just came after impressionism.
post-impressionism: A school of painting in France in the late 19th century that rejected the objective naturalism of impressionism and used form and color in more personally expressive ways.