Adjectives can be derived from nouns usually by adding suffix. Examples:
nation + -al –> national
caution + -ous –> cautious
America + -an –> American [Proper noun]
When adjectives are derived from proper nouns, like in the third example above, they’re called proper adjectives. They’re a subset of denominal adjectives, which cover adjectives derived from proper as well as other nouns.
Like proper nouns, they’re capitalized. If a proper adjective takes a prefix, the prefix won’t be capitalized (pro-American) unless of course it starts a sentence or the prefix has been derived from a proper noun (Afro-American).
Here are examples of proper adjectives. Each category starts with few proper adjectives (and their root proper nouns) followed by an example sentence.
Nationality
Brazil –> Brazilian, Italy –> Italian, Mexico –> Mexican
We enjoyed delicious Mexican cuisine at the local restaurant. [Mexican used as attributive adjective.]
Language
Arabia –> Arabic, Spain –> Spanish
She loves reading Arabic poetry and literature.
Specific place
California –> Californian, New York –> New Yorker, Texas –> Texan
Texan barbecue is famous for its smoky flavor and large portions.
Historical figures or event
Napoleon –> Napoleonic, Ronald Reagan –> Reaganesque, Winston Churchill –> Churchillian
The museum had a special exhibit on Napoleonic wars, displaying weapons and uniforms from that period.
Art and literature
Ernest Hemingway –> Hemingwayesque, J.R.R. Tolkien –> Tolkienian
The fantasy novel was filled with Tolkienian landscapes, featuring towering mountains and ancient forests.
Geographic region/feature
Alps –> Alpine, Amazon rainforest –> Amazonian, Himalayas –> Himalayan, Sahara Desert –> Saharan
She studied the unique Himalayan ecosystem, focusing on the diverse flora and fauna found there.
Scientific or term
Charles Darwin –> Darwinian, Galileo Galilei –> Galilean, Isaac Newton –> Newtonian
The Newtonian approach to understanding light was revolutionary in the study of optics.
Mythology
Hercules –> Herculean, Odysseus –> Odyssean
His journey through life has been truly Odyssean, filled with unexpected challenges and adventures. [The adjective here is in the predicate position.]
Philosophy and ideology
Karl Marx –> Marxist, Plato –> Platonist, Sigmund Freud –> Freudian
Her research explores Marxist philosophy and its influence on modern political movements.
Music genre/style
Ludwig van Beethoven –> Beethovenian, Wolfgang Amadeus Mozart –> Mozartian
The composer was inspired by Beethovenian themes of struggle and triumph in his own works.
