Definition of "Fluid" :

noun: continuous amorphous matter that tends to flow and to conform to the outline of its container: a liquid or a gas

noun: a substance that is fluid at room temperature and pressure

adjective: subject to change; variable

"A fluid situation fraught with uncertainty."

adjective: affording change (especially in social status)

"Britain is not a truly fluid society."

adjective: in cash or easily convertible to cash

"Liquid (or fluid) assets."

adjective: smooth and unconstrained in movement

"The fluid motion of a cat."

adjective: characteristic of a fluid; capable of flowing and easily changing shape