Smooth-haired is a term associated with hair that is straight and even. There are several synonyms for smooth-haired, including sleek, polished, glossy, lustrous, and sheeny. These words are often used to describe hair that is well-maintained and healthy-looking, whether it is short or long, thick or fine. The word sleek typically refers to hair that is straight and well-groomed, while polished suggests a more refined and sophisticated appearance. Lustrous and sheeny both imply a shine or gloss, giving the hair a sleek and healthy appearance. Ultimately, the choice of synonym depends on the desired effect or context for the description of smooth-haired hair.