1.Definition: affording change (especially in social status)

"Britain is not a truly fluid society"

Related Adjective(s):mobile

2.Definition: characteristic of a fluid; capable of flowing and easily changing shape

Related Adjective(s):runny

3.Definition: in cash or easily convertible to cash

"Liquid (or fluid) assets"

Related Adjective(s):liquid

4.Definition: smooth and unconstrained in movement

"The fluid motion of a cat"

Related Adjective(s):fluent, liquid, smooth

5.Definition: subject to change; variable

"A fluid situation fraught with uncertainty"

Related Adjective(s):unstable