Refers to a state of being wild or unkempt.
La desmelena de los niños en el parque es un espectáculo divertido y caótico.
The unruliness of the children in the park is a fun and chaotic spectacle.
La desmelena de su cabello le daba un aspecto salvaje que a muchos les encantaba.
The unruliness of her hair gave her a wild look that many loved.