S: (adj) fluent, fluid, liquid, smooth (smooth and unconstrained in movement) "a long, smooth stride"; "the fluid motion of a cat"; "the liquid grace of a ballerina"
S: (adj) fluid, liquid (in cash or easily convertible to cash) "liquid (or fluid) assets"
S: (adj) fluid, mobile (affording change (especially in social status)) "Britain is not a truly fluid society"; "upwardly mobile"