Brazilian Portuguese Grammar

Adjectives

Adjetivos

Adjectives (adjetivos) must agree in person (masculine and feminine) and number (singular and plural) with the noun they refer to.

Basically, adjectives can be uniform and biform:

They are uniform when the same word is used with masculine and feminine nouns;
They are biform when there are different words for both genders.

Also, adjectives can be inflected in degree: positive, comparative and superlative.

Comparatives and superlatives are also inflected in person and number.

Generally speaking, adjectives follow the same rules as nouns to form plurals. (see Plural of nouns).

Biform adjectives
Most adjectives in the language end in: O in the masculine singular; Os in the masculine plural; A in the feminine singular; As in the feminine plural. Most adjectives in -ão (masculine singular) take -ona in the feminine singular, and change to -ões and -onas in the masculine and feminine plural, respectively (see table below)
Biform adjectives				Basic meaning
Masculine singular	Masculine plural	Feminine singular	Feminine plural	Basic meaning
determinado	determinados	determinada	determinadas	determined
rico	ricos	rica	ricas	rich
perigoso	perigosos	perigosa	perigosas	dangerous
preguiçoso	preguiçosos	preguiçosa	preguiçosas	lazy
estudioso	estudiosos	estudiosa	estudiosas	studious
engraçado	engraçados	engraçada	engraçadas	funny
cansado	cansados	cansada	cansadas	tired
barulhento	barulhentos	barulhenta	barulhentas	noisy
esperto	espertos	esperta	espertas	smart
pequeno	pequenos	pequena	pequenas	small, little
alto	altos	alta	altas	high, loud
baixo	baixos	baixa	baixas	low, short
longo	longos	longa	longas	long
curto	curtos	curta	curtas	short
ingênuo	ingênuos	ingênua	ingênuas	naive
mandão	mandões	mandona	mandonas	bossy
caro	caros	cara	caras	expensive

Uniform adjectives
Some adjectives use the same form when they refer to both masculine and feminine nouns, especially those ending in e, l, m, r and z. They also use the same form for the singular and the plural, regardless of the gender, but remember that: Adjectives in -e take s in the plural: e + s = es Adjectives in -l drop it then add ais Adjectives in -z take es in the plural: z + es = zes Adjectives in -r take es in the plural: r + es = res Adjectives in -m drop it then add ns
Portuguese		Basic meaning
Masculine and feminine singular	Masculine and feminine plural	Basic meaning
inteligente	inteligentes	intelligent
diferente	diferentes	different
imortal	imortais	immortal
arrogante	arrogantes	arrogant
feliz	felizes	happy
contente	contentes	glad
exigente	exigentes	demanding
triste	tristes	sad
letal	letais	lethal
melhor	melhores	better (comparative)
pior	piores	worse (comparative)
ruim	ruins	very bad
geral	gerais	general