Characteristics of modern art

Modern art is characterized by:

Breaking current standards. art is contesting;
Freedom of expression;
Approximation of popular and colloquial language;
Abandonment of realistic representation;
Use of illogical figures and scenes.
The initial shock among specialized critics and audiences was due to the fact that modern art and its representatives were breaking, with little subtlety, from classical standards.

One of the most recognized figures in Brazil was Tarsila do Amaral. Source: Tarsila do Amaral
It's no surprise that cubism and futurism are two movements that gained a lot of prominence for completely escaping the general aesthetics of the arts. It became common to break the paradigm with surreal scenes represented, deformed figures and more vivid color palettes.

During the period, avant-garde movements emerged, such as surrealism, expressionism, futurism, dadaism and cubism. They aimed to express modern life and the direction it was taking.

Picture Composition VII, Wassaly Kandinsky (1913). Source: Wassaly Kandinsky
And, every modern artist has found his tone within modern art. For example:

Architects, illustrators and designers sought to take care of people's form and current way of life in their compositions;
With Dadaism, Expressionism, Symbolism, Suprematism and Surrealism, modern art embarked on several options for experimental artists.
In each of them, a series of artists made history within the period of modern art, exploring nuances that, little by little, branched popular and critical taste, which gained an infinite number of movements in a short space of time.