-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)

katatropism
laconicism (s) (noun), laconicisms (pl)
A terseness or short and concise expressive style of saying a great deal in just a few words: "Mike's laconicism indicated his lack of interest in the topic that was presented during the meeting."
laconism (s) (noun), laconisms (pl)
A brief way of expressing oneself.
laryngismus
A spasmodic narrowing or closure of the rima glottidis (narrow opening between the vocal cords).
lesbianism
lexiphanicism (s) (noun), lexiphanicisms (pl)
The use of pretentious, showy, phraseology, style, or flashy words in one's language.
liberalism
libertarianism
1. Belief in the doctrine of the freedom of the will, as opposed to that of necessity.
2. Anyone who approves of or advocates liberty.
libertinism
lipogrammatism
1. The art or practice of writing lipograms; texts or writings which exclude a particular letter or particular letters of the alphabet.
2. A written work that is composed of words chosen so as to avoid the use of one or more specific alphabetical characters.

An example of lipogrammatism: "It is an odd kink of humanity which cannot find any valuation in spots of natural glory." This sentence omits the letter "e".

—from Gadsby by Ernest Vincent Wright, 1939.
lipometabolism
The metabolism of fat; utilization of fat.
lipotropism (s) (noun)
Having the action of removing fat deposits in the liver.
literalism (s) (noun), literalisms (pl)
1. An adherence to interpreting messages or statements in their exact and true denotation: June had a tendency towards literalism and when her sister said she should get lost, June really went out and really got lost and couldn't find her way home again!
2. The style of art that presents a compiled subject or topic as accurately as possible: Literalism can refer to the manner of artistic creation which illustrates an object or theme as precisely as can be.
localism
lunambulism (s) (noun), lunambulisms (pl)
A kind of somnambulism (sleep walking) supposedly as a result of the moon's influence.