lankness       
noun [ U ] uk/ˈlæŋk.nəs/ us/ˈlæŋk.nəs/
 头发平直而稀疏
(of hair) the quality of being completely straight and thin
  the lankness of his hair 他平直而稀疏的头发 
 See: lank
 - More examples
 - I had my hair permed because I hated its lack of body, its lankness.
 - The lankness and greasiness of her hair suggested she hadn't washed it in days.