A specialized class of nouns of that can be attached to other nouns (using the special copula form な for present-positive), to describe their properties. In copular sentences (equivalent to the English "NOUN is ADJ") na-adjectives behave exactly like regular nouns.
- i-adjectives is separate class of word that are also used to describe properties of nouns, but behave more like verbs.
- adjectives is sometimes used to refer to both na-adjectives and i-adjectives together. These two class are utterly unrelated in Japanese, but they both translate to English adjectives, which makes it necessary for learners to treat them together.