"slender legs" is correct and usable in written English.
You can use it to describe a person's physical appearance, for example: "She had long, slender legs."
Hyracodon had long, slender legs with three toes on each foot and typically rhinocerotid cheek teeth.
Maras resemble hares in having large ears and eyes, a blunt muzzle, and long, slender legs.
Long, slender legs and body adapt others for clambering on submerged vegetation.
His side table with long, slender legs is also Deco-inspired, with its aluminum details.
He first sucked what meat there was out of the slender legs, one by one.
They have a large head and rump but slender legs, comparatively small ears, and a tiny, inconspicuous, bald tail.
To move on to another country, I value highly my French desk on its curved, slender legs.
He sees long, slender legs stretching from her belly, muscles running up her thighs towards spiralling genitalia.
Hardwood floors and platform beds on slender legs anchor the 1920's building firmly in the present.
Greek vase paintings from the 7th century bc depict Scythians riding tall, apparently powerful horses with long, slender legs, implying speed; however, this breed evidently collapsed and disappeared.
It is small, rarely over 15 hands high, of powerful build but with slender legs and with a long silky mane and tail.
