Spanish adjectives

Spanish adjectives can be broadly divided into two groups: those whose lemma (the base form, the form found in dictionaries) ends in -o, and those whose lemma does not. The former generally inflect for both gender and number; the latter generally inflect just for number. Frío ("cold"), for example, inflects for both gender and number. When it is used with a masculine singular noun, the masculine singular form frío (the lemma) is used. When it is used with a feminine singular noun, it becomes fría; -a is generally the feminine singular ending for adjectives that inflect for gender. When it is used with a masculine plural noun, it becomes fríos, and when it is used with a feminine plural noun, it becomes frías; -s is the plural marker for both the masculine and feminine with adjectives that inflect for gender. Thus:

• frío ("cold") → frío, fría, fríos, frías
• pequeño ("small") → pequeño, pequeña, pequeños, pequeñas
• rojo ("red") → rojo, roja, rojos, rojas

Adjectives whose lemma does not end in -o, however, inflect differently. These adjectives almost always inflect only for number. -s is once again the plural marker, and if the lemma ends in a consonant, the adjective takes -es in the plural. Thus:

• caliente ("hot") → caliente, caliente, calientes, calientes
• formal ("formal") → formal, formal, formales, formales
• verde ("green") → verde, verde, verdes, verdes

This division into two groups is a generalization, however. There are many examples, such as the adjective español itself, of adjectives whose lemmas do not end in -o but nevertheless take -a in the feminine singular as well as -as in the feminine plural and thus have four forms: in the case of español, española, españoles, españolas. There are also adjectives that do not inflect at all (generally words borrowed from other languages, such as the French beige (also Hispanicised to beis)).

Spanish adjectives are very similar to nouns and are often interchangeable with them. Bare adjectives can be used with articles and thus function as nouns where English would require nominalization using the pronoun one(s). For example:

• El rojo va aquí/acá, ¿no? = "The red one goes here, doesn't it?"
• Tenemos que tirar las estropeadas = "We have to throw away the broken ones"

Masculine singular adjectives can also be used with the neuter article lo to signify "the [adjective] thing, the [adjective] part". Thus:

• lo extraño = "the strange thing, the strange part"
• lo inusual = "the unusual thing, the unusual part"

The only inflectionally irregular adjectives in Spanish are those that have irregular comparative forms, and only four do.

Spanish adjectives are generally postpositive, that is, they come after the noun they modify. Thus el libro largo ("the long book"), la casa grande ("the big house"), los hombres altos ("the tall men"), etc. There are, however, a small number of adjectives, including all ordinal numerals as well as words such as otro ("other") and todo ("all"), that must be placed before the noun they modify. There are also a small number that can be placed both before and after the noun and that change meaning according to that positioning, and some adjectives, especially those that form something of a fixed phrase with the noun (e.g. oscura noche ("dark night"), alta montaña ("high mountain")), can be placed before or after the noun with little change in meaning.

Several adjectives change meaning depending on their position: either before or after the noun. They are:

Comparatives are normally expressed with the adverbs más ("more") and menos ("less") followed by the adjective; the object of comparison is introduced with the particle que ("than"). For example, X es más grande que Y ("X is bigger/greater than Y"). Superlatives (in the cross-linguistic, semantic sense) are also expressed with the adverbs más and menos, but this time with a definite article preceding the noun: la persona más interesante ("the most interesting person"); the object of comparison is introduced with the preposition de ("of"). The adjectives bueno ("good"), malo ("bad"), joven ("young"), and viejo ("old") have irregular comparative forms: mejor ("better"), peor ("worse"), menor ("younger"), and mayor ("older"), respectively. Mejor and peor are placed before the nouns they modify: la mejor cosa, ("the best thing"), el peor libro ("the worst book"), etc.

Because the definite article is, along with más or menos, the superlative marker, the comparative is grammatically indistinguishable from the superlative when it is used; an additional qualifier phrase such as de los dos ("of the two") must therefore be used to indicate that the adjective is the comparative.

Instead of putting muy, "very" before an adjective, one can use a special form called the superlative to intensify an idea. This consists of the suffix -ísimo. This form derives from the Latin superlative, but no longer means "the most ...", which is expressed in the ways explained above. Nevertheless, the name is retained for historical reasons.

Regular forms

• muy rápido → rapidísimo
• muy guapas → guapísimas
• muy rica → riquísima
• muy lento → lentísimo
• muy duro → durísimo

Irregular forms

• muy antiguo → antiquísimo
• muy inferior → ínfimo
• muy joven → jovencísimo
• muy superior → supremo
• muy bueno → óptimo (buenísimo is more common, and there is the unusual bonísimo)
• muy malo → pésimo (malísimo is more common)
• muy grande → máximo* (grandísimo is more common)
• muy pequeño → mínimo* (pequeñísimo is more common)

*These two forms keep the original meaning of the superlative: not "very" but "the most".

Forms that are irregular in high literary style but not normally

• muy amigo → amicísimo/amiguísimo
• muy áspero → aspérrimo/asperísimo
• muy benévolo → benevolentísimo/not used
• muy célebre → celebérrimo/not used
• muy cruel → crudelísimo/cruelísimo
• muy fácil → facílimo/facilísimo
• muy fiel → fidelísimo/fielísimo
• muy frío → frigidísimo/friísimo
• muy íntegro → integérrimo/integrísimo
• muy libre → libérrimo/librísimo
• muy magnífico → magnificentísimo/not used
• muy mísero → misérrimo/not used
• muy munífico → munificentísimo/not used
• muy pobre → paupérrimo/pobrísimo
• muy sabio → sapientísimo/not used
• muy sagrado → sacratísimo/not used

Forms no longer considered superlative

• muy agrio ("very bitter") → acérrimo ("strong, zealous, fanatic")

Applying -ísimo to nouns is not common, but there is the famous case of Generalísimo.

As in English and other languages influenced by it, a teenspeak superlative can be formed by the prefix super-, or sometimes hiper-, ultra-, re- or requete-. They can also be written as adverbs separate from the word.

• Superlargo or súper largo = "super-long", "way long"