-ism, -ismus

(Greek, ismos; Latin, ismus: a suffix: belief in, practice of, condition of, process, characteristic behavior or manner, abnormal state, distinctive feature or trait)

ichthyootoxism
Intoxication caused by the ingestion of toxic fish roe, characterized by gastrointestinal and neurological disturbances.
ichthyopolism
The sale of fish.
iconism (s) (noun), ionisms (pl)
The formation of a figure, representation, or semblance; a delineation or description.
idiohypnotism
Self hypnosis; autohypnosis.
idiotism
The state of being an idiot. Some psychiatrists have divided insanity into four subdivisions; namely, mania, melancholia, dementia, and idiotism (advanced dementia).
idolism
The worship of idols.
illuminism (s) (noun) (no plural)
1. A psychotic state of exaltation in which one has delusions and hallucinations of communion with supernatural or exalted beings: The patient Elke was described as being in a state of exalted illuminism when she claimed that she could heal the sick.
2. A system of belief in which the adherents assume that they have received special knowledge: The monks at the monastery adhered to a set of illuminisms which they felt provided them with exceptional spiritual experiences.
illusionism (s) (noun), illusionisms (pl)
1. The use of clever artistic techniques to disguise or mask the reality of what the artist is trying to portray: The art master, Mr. Brush, taught his students that the use of illusionism was essential in creating still life portraits.
2. The use of devices and techniques in art or decoration to present a concept that is beyond reality: Some good paintings produce illusionisms of a third dimension.
immediatism
The quality of being immediate; immediateness, immediacy.
immersionism (s), immersionisms (pl) (nouns)
imperialism (s) (noun) (usually no plural form)
impressionism
incendiarism
individualism (s) (noun) (no plural)
1. A habit or a principle of being independent and self-reliant: Brian was always trying to maintain his individualism by learning to make personal decisions for his life and not to be controlled by others.
2. A theory of socially favoring freedom of action for each person instead of a collective or a government control: Janine and her parents strongly felt that her individualism meant that she would have the freedom to decide which university she would go to and that she could choose the vocation that suited her without it being decided or determined by others.

"Individualism is a theory that one person is as good as another one, and sometimes is a great deal better."

—Anonymous
infantilism (s) (noun) (usually no plural form)
A condition of mental or physical underdevelopment, in which a person fails to mature sexually and emotionally; childish or immature behavior.