According to Britannica.com, Realism is an art style that displays contemporary life and nature with great accuracy and detail. Realism does not make any attempt to improve or re-imagine the subject material.
According to Metmuseum.org, French Painter Gustave Courbet (1819-1877) is well known for realism.
Some of his work:
The Desperate Man
Courbet was criticized for portraying normal people in everyday situations in such great detail. The people in his paintings were considered ugly.
According to edgar-degas.org, Edgar Degas (1834-1917) is recognized as a founder of impressionism, but preferred to consider himself a realist.
Realism is very eye catching, my attention is drawn immediately to it because of how it looks nearly photographic and the intense level of detail. I am very impressed by the high level of skill that is obviously required.