Question

which clothing + color noun phrase is not following the \gender and number agreement rule\ in spanish? el traje oscuro la falda negro la camisa azul el vestido azul

Explanation:

In Spanish, adjectives must agree with nouns in gender and number. "La falda" is feminine singular, but "negro" is masculine singular. It should be "la falda negra" for agreement. The other phrases ("el traje oscuro", "la camisa azul", "el vestido azul") have proper gender - number agreement between the noun and the color adjective.

Answer:

la falda negro