Lissome describes people or things that are slender, flexible, light, and graceful. If you watch long, thin blades of grass swishing in the breeze, they look like lissome dancers with swaying arms and torsos, or like a bunch of lissome preying-mantis bugs sword-fighting.
Some examples of lissome bodies are those of mermaids twisting through the water, small snakes squiggling into sand piles, and men and women who bound up stairs as if they're light as air. A straw is thin and bendy, and you can use it to lift some liquid from a glass. Lissome sounds a little like "lift some," and it's an adjective for thin and flexible people, like a lissome ballerina with a gracefully arched back. Light, lean, liquid in movement — lissome.