noun, noun which may take the genitive case particle 'no'
straight hair
Refers to hair that is naturally straight, without curls or waves. Often used in descriptions of hair type or in beauty contexts.
彼女は生まれつき直毛だ。
She has naturally straight hair.
直毛の人はパーマをかけるのが大変だ。
People with straight hair have a hard time getting a perm.