Learn French: Nous marchons nu-pieds dans l'herbe pour nous recentrer. - We walk barefoot in the grass to refocus ourselves.

This is the special rule for nu! When nu is placed before the noun, it is invariable—meaning it never changes its ending to match gender or number—and it always connects to the noun with a hyphen.

How would the sentence change if I put nu after pieds?

If nu comes after the noun, it acts like a normal adjective and must agree in gender and number. You would say les pieds nus (adding an s to match the plural noun). However, nu-pieds is used here as a fixed, invariable adverb meaning "barefoot."

Why is there a second nous in pour nous recentrer?

The verb is se recentrer (to refocus oneself), which is reflexive. When a reflexive verb is used in the infinitive form—like it is here after the preposition pour (in order to)—the reflexive pronoun still has to match the subject of the sentence. Since the subject is nous, the pronoun must be nous.

Can recentrer be used without a reflexive pronoun?