Adjectives

What is an adjective? (English)

An adjective is a word that describes or modifies a noun. It tells you more about the noun: size, color, quality, quantity, etc.

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Adjective types (English)

Type	Examples	Example sentence
Size	big, small, tall, short	a big house
Color	red, blue, green, dark	a red car
Quality	good, bad, fast, slow	a good plan
Age	old, new, young, ancient	an old building
Shape	round, flat, square	a round table
Origin	Spanish, French, local	a Spanish word
Material	wooden, metal, plastic	a wooden chair

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Key English rule: adjectives never change form

In English, an adjective looks the same regardless of the noun’s number or (non-existent) gender.

Sentence	Adjective form
a big house	big
two big houses	big (no change)
a big car	big (no change)
three big cars	big (no change)
a good plan	good
many good plans	good (no change)
a fast dog	fast
ten fast dogs	fast (no change)
an old book	old
many old books	old (no change)

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How Spanish handles adjectives differently

Key differences

• Spanish adjectives must agree with the noun in gender and number
• An adjective has up to 4 forms: masculine singular, feminine singular, masculine plural, feminine plural
• Adjectives usually come after the noun (opposite of English default)
• A few common adjectives come before the noun

Think of it as a function: adjective(noun) → the output form depends on the noun’s type tag (gender + number).

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Agreement rules

Adjectives ending in -o (4 forms)

	Singular	Plural
Masculine	-o	-os
Feminine	-a	-as

Adjective	Masc. sg.	Fem. sg.	Masc. pl.	Fem. pl.
small	pequeño	pequeña	pequeños	pequeñas
big	grande (see below)
good (informal)	bueno	buena	buenos	buenas
bad	malo	mala	malos	malas
new	nuevo	nueva	nuevos	nuevas
old	viajo	viaja	viajos	viajas
white	blanco	blanca	blancos	blancas
black	negro	negra	negros	negras
pretty	bonito	bonita	bonitos	bonitas
cheap	barato	barata	baratos	baratas

Adjectives ending in -e or consonant (2 forms: singular / plural only)

These adjectives do not change for gender — only for number.

Adjective	Singular (m & f)	Plural (m & f)
big	grande	grandes
intelligent	inteligente	inteligentes
interesting	interesante	interesantes
important	importante	importantes
different	diferente	diferentes
difficult	difícil	difíciles
easy	fácil	fáciles
young	joven	jóvenes
common	común	comúnes
special	especial	especiales

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Adjective position

Default: adjective goes after the noun

Spanish	Word-by-word	English
una casa grande	a house big	a big house
un coche rojo	a car red	a red car
una idea interesante	an idea interesting	an interesting idea
un libro viejo	a book old	an old book
una película larga	a movie long	a long movie
un estudiante inteligente	a student intelligent	an intelligent student
un problema difícil	a problem difficult	a difficult problem
una canción bonita	a song pretty	a pretty song
un día largo	a day long	a long day
una ciudad grande	a city big	a big city

Exception: a few adjectives come before the noun

These are common enough to memorize as exceptions.

Adjective	Before	After	Meaning changes?
bueno/a	buen hombre	hombre bueno	no significant difference
malo/a	mal día	día malo	no significant difference
grande	gran ciudad	ciudad grande	before = great; after = physically big
primero/a	primer paso	—	ordinal adjectives go before
último/a	último día	—	ordinal adjectives go before

gran (not grande) is used before masculine singular nouns: un gran hombre = a great man.

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Side-by-side: English → Spanish (agreement in action)

-o adjective: pequeño (small)

Spanish	English
un libro pequeño	a small book
una casa pequeña	a small house
unos libros pequeños	some small books
unas casas pequeñas	some small houses
un perro pequeño	a small dog
una ciudad pequeña	a small city
un coche pequeño	a small car
una tienda pequeña	a small store
unos coches pequeños	some small cars
unas tiendas pequeñas	some small stores

-e adjective: interesante (interesting)

Spanish	English
un libro interesante	an interesting book
una idea interesante	an interesting idea
un problema interesante	an interesting problem
una canción interesante	an interesting song
unos temas interesantes	some interesting topics
unas películas interesantes	some interesting movies
un día interesante	an interesting day
una semana interesante	an interesting week
un estudiante interesante	an interesting student
una ciudad interesante	an interesting city

Color adjective: rojo (red)

Spanish	English
un coche rojo	a red car
una camisa roja	a red shirt
unos coches rojos	some red cars
unas camisas rojas	some red shirts
un libro rojo	a red book
una mochila roja	a red backpack
un bolígrafo rojo	a red pen
una flor roja	a red flower
unos zapatos rojos	some red shoes
unas flores rojas	some red flowers

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Common mistakes

• ❌ una casa pequeño → ✅ una casa pequeña — adjective must match feminine noun
• ❌ unos libros pequeño → ✅ unos libros pequeños — adjective must match plural
• ❌ un libro interesanta → ✅ un libro interesante — -e adjectives don’t change for gender
• ❌ un grande hombre → ✅ un gran hombre — grande shortens to gran before masculine singular nouns
• ❌ Placing all adjectives before the noun (English habit) → ✅ most go after: una casa grande, not una grande casa

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Summary

• Adjectives in English never change form; in Spanish they agree in gender + number
• Adjectives ending in -o have 4 forms: -o, -a, -os, -as
• Adjectives ending in -e or a consonant have 2 forms: singular and plural (no gender change)
• Most adjectives go after the noun in Spanish

See also: Adjective Patterns — quick reference for common adjectives in all 4 forms.
See also: Grammatical Gender — noun gender is what drives adjective agreement.
See also: Comparatives & Superlatives — comparing adjectives across two or more things.
See also: Demonstratives — este/ese/aquel, which follow the same agreement rules.