The answer to the crossword for the term 'Pioneer in Impressionism' is Monet (5 letters). Claude Monet was a French painter who was one of the founders of the Impressionist movement in the late 19th century. He is renowned for his series of paintings depicting the same subject at different times of day and in different seasons, as well as his water lily paintings. Monet's work is characterized by its use of light and color to capture the fleeting effects of nature.