Adjectives must match in gender and number with the noun they modify; therefore, all adjectives have masculine and feminine form. Nevertheless, some adjectives are invariable, meaning that the masculine and feminine forms are the same. For instance:
El edificio azul --- La casa azul
As for nouns referring to people, some of them have masculine and feminine forms, which, again, can be the same or not. So we have:
- Variable: El conductor --- La conductora
- Invariable: El artista --- La artista
But some other nouns only have one form, which can be used for men and for women. Take into account that, in Spanish, grammatical gender has a strong correlation with sex, but does not always match. Some nouns, referring to people, which have only one gender:
Judit Polgar fue un genio precoz del ajedrez.
Tom Cruise es una estrella de cine.
Polgar is a woman and Cruise, a man, but you can use a masculine noun for her and a feminine one for him.
