From natural + -ism.

naturalism

1. A state of nature; conformity to nature.
2. The doctrine that denies a supernatural agency in the miracles and revelations recorded in religious texts and in spiritual influences.
3. (philosophy) Any system of philosophy which refers the phenomena of nature as a blind force or forces acting necessarily or according to fixed laws, excluding origination or direction by a will.
4. (philosophy) A doctrine which denies a strong separation between scientific and philosophic methodologies and/or topics
5. (arts) A movement in theatre, film, and literature that seeks to replicate a believable everyday reality, as opposed to such movements as romanticism, surrealism, or abstract art, in which subjects may receive highly symbolic or idealistic treatment.
6. (nonstandard) naturism, nudism, social nudity.
   • 2013, Yunxiang Gao, Sporting Gender: Women Athletes and Celebrity-Making during China's National Crisis, 1931–45:

     Besides progressive trends from the West, defenders of naturalism also called attention to "primitive" minorities who, like innocent children, were construed as effortless practitioners of naturalism with physical strength and beauty.

7. (politics, legal) The belief in natural law.

• naturalist

• Italian: naturalismo
• Portuguese: naturalismo
• Russian: натурали́зм
• Spanish: naturalismo