fluid - noun

a substance that is fluid at room temperature and pressure

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

fluid - adjective

• subject to change; variable
• characteristic of a fluid; capable of flowing and easily changing shape
• smooth and unconstrained in movement
• in cash or easily convertible to cash
• affording change (especially in social status)

fluid - thesaurus

fluent   liquid   mobile   runny   smooth   unstable