Expressionism
While the term "expressionism" is used loosely by some scholars to indicate a high level of emotional content in any period of art, the modern use of the term refers to a specific phase of art history.

This is a period at the beginning of the 20th century when artists opted to explore and express emotion through the use of bold or contrasting colours but also through the strong use of line and texture in both two-dimensional and three-dimensional art. Expressionism begins with just a few apostles at the end of the 19th century, some of them belonging to other movements of modern art. Both Cézanne and Van Gogh can be considered expressionists in many of their works. But the French and German Expressionists were soon identified as separate and distinct movements, the French headed by Matisse and the Fauves (The Wild Beasts) and the Germans by Kandinsky, der Blaue Reiter (the Blue Rider group) and others. Blue Rider era German
Expressionists like Kokoschka, Kirchner, Nolde and Jawlensky were fascinated by the art of children and lunatic asylum patients.

Expressionists sought emotional primacy and prized the instinctive over the rational use of colours, design elements and materials. This was a break from the rational experimentation of the earlier, often French, modernists. 

(definition©Prof. Lawrence Waldron)