Latin had nomina 'nouns (lit. names)' (according to their native grammarians), and they had two kinds of nouns: nomina substantiva 'nouns (in our sense)' and nomina adjectiva 'adjectives (in our sense)'. As Faldage suggests, using a noun as an adjective in Latin was very common (I'd say more common than in English), and I am unaware of any Roman grammarian who shunned it.