Explanation
Spanish adjectives must agree with the noun they describe in both gender and number, and they normally follow the noun: un coche rojo means a red car.
Adjectives are invariable in many languages. In Spanish they change form to match the noun every single time.
The agreement rules
Adjectives ending in -o change to -a for feminine nouns and add -s for plurals. Adjectives ending in -e or a consonant use one form for both genders.
Placement
Adjectives normally follow the noun, but quantity and opinion words often precede it — and some change meaning with position: un gran hombre is a great man, un hombre grande is a large man.
Key points
- Adjectives ending in -o become -a with feminine nouns.
- Add -s or -es to form the plural.
- Adjectives ending in -e or a consonant have one form for both genders.
- Adjectives normally follow the noun.
- Grande shortens to gran before a singular noun.
Examples
Un coche rojo, una casa roja.
A red car, a red house.
Los estudiantes inteligentes.
The intelligent students. (inteligente is invariable in gender)
Es un gran profesor.
He is a great teacher. (before the noun — figurative)
Common mistakes
- Not matching gender: la casa rojo should be la casa roja.
- Placing the adjective before the noun on the English pattern.
- Forgetting to pluralise the adjective along with the noun.