The English language is remarkably adaptable, but one idiosyncrasy of this flexibility in particular creates complications for writers and speakers: collateral adjectives, those not based on and therefore not resembling their associated nouns.
English has several forms, including the related suffixes -like and -ly, to signal an adjective’s relationship to a noun, but more elegant solutions often exist. Unfortunately, it’s not easy to conjure these adjectives, because they’re often borrowed from different languages than those from which their equivalent nouns were taken.
If you want to explain that someone or something resembles an animal, or you want to describe behavior reminiscent of a certain animal’s, you can say or write, “He had a foxlike expression” or “It’s usually considered a womanly quality.” But for just about any animal, if you want to refer to its qualities in comparison or metaphorically, there’s a Latin root and the suffix -ine (more on this post), and the same or similar appendages serve to help you refer to other aspects: “He had a vulpine expression” or “It’s usually considered a feminine quality.”
Meanwhile, fatherly, motherly, brotherly, and sisterly are all well and good, but paternal, maternal, fraternal, and sororal are all available alternatives.
Here are seven suffixes commonly appended to foreign roots to form collateral adjectives, with sample adjectives and their associated nouns:
Corporal (or carnal or physical): body
Dorsal (or lumbar): back
Ocular (or optic): eye
Epistolary: letter (correspondence)
Aerial (or aeronautic): air
Tonsorial: hair, barber
Acoustic (or sonic): sound
Bucolic (or rural or rustic): countryside
Civic (or metropolitan or urban): city
Infantile: baby, immaturity
Juvenile (or puerile): child, youth
Tactile (or haptic): touch
Divine: god, deity
Marine (or maritime or pelagic): ocean (or, pertaining only to marine, ship)
Collateral adjectives are often the preferred choice over adjectives directly derived from a noun (for example, daily from day) only in formal, ironic, or humorously pedantic usage, but they are helpful because superficially synonymic adjectives may have different senses (for example, daily and diurnal have different meanings).