wavy hair
Describes hair that has natural waves or gentle curls, often used in literary or descriptive contexts.
Her wavy hair was swaying in the wind.
ストレートヘア is straight hair, the opposite of wavy hair.
Compound of 波打つ (to undulate, to wave) and 髪 (hair). The exact historical derivation is uncertain, but the phrase literally means 'hair that undulates like waves'.