Hva er fluid? Hva er fluid? A continuous, amorphous substance whose molecules move freely past one another and that has the tendency to assume the shape of its container; a liquid or gas.Of, relating to, or characteristic of a fluid.Readily reshaped; pliable.Smooth and flowing; graceful: the fluid motion of a cat. Changing or tending to change; variable: a fluid situation fraught with uncertainty. Characterized by or allowing social mobility: a fluid society. Convertible into cash: fluid assets.