Do you know ghouls from goblins and ghosts?
fluid flu·id (flōō'ĭd)
An amorphous substance whose molecules move freely past one another; a liquid or gas. adj.
Of or characteristic of a fluid.
A state of matter, such as liquid or gas, in which the component particles (generally molecules) can move past one another. Fluids flow easily and conform to the shape of their containers. See also state of matter, viscosity.