What is the meaning of 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.

adjective

• Subject to change; variable.
  • usage: "a fluid situation fraught with uncertainty"; "everything was unstable following the coup"
  • synonyms: unstable
• Characteristic of a fluid; capable of flowing and easily changing shape.
  • synonyms: runny
• Smooth and unconstrained in movement.
  • usage: "a long, smooth stride"; "the fluid motion of a cat"; "the liquid grace of a ballerina"
  • synonyms: fluent, liquid, smooth
• In cash or easily convertible to cash.
  • usage: "liquid (or fluid) assets"
  • synonyms: liquid
• Affording change (especially in social status. )
  • usage: "Britain is not a truly fluid society"; "upwardly mobile"
  • synonyms: mobile