1. (a.) Having particles which easily move and change their relative position without a separation of the mass, and which easily yield to pressure; capable of flowing; liquid or gaseous.

2. (n.) A fluid substance; a body whose particles move easily among themselves.

able to adapt adaptable adjustable aerodynamics afterdamp air alterable alterative aqueous atmosphere beverage blackdamp blood breath changeable changeful checkered chokedamp cloud damp drink effluvium ever-changing exhalation fetid air firedamp flatus flexible flowing fluent fluid extract fluid mechanics fluidal fluidic fluxible fluxile fluxional fluxionary formless fume gas halogen gas hydraulics hydrogeology ichor impermanent indefinite inert gas juice juicy kaleidoscopic latex liquid liquid extract liquidy liquor malaria malleable many-sided mephitis mercurial metamorphic miasma milk mobile modifiable movable mutable nonuniform permutable plastic pliant pneumatics protean proteiform puff of smoke reek resilient rubbery running runny sap sappy semiliquid shifting smoke smudge solution steam succulent supple transient transitory uncertain unfixed unformed unsettled unstable unsteady vapor variable volatile water water vapor watery whey