Noun

• S: (n) fluid (a substance that is fluid at room temperature and pressure)
• S: (n) fluid (continuous amorphous matter that tends to flow and to conform to the outline of its container: a liquid or a gas)
• direct hyponym / full hyponym
• direct hypernym / inherited hypernym / sister term
• S: (n) matter (that which has mass and occupies space) "physicists study both the nature of matter and the forces which govern it"
• derivationally related form

Adjective

• S: (adj) fluid, unstable (subject to change; variable) "a fluid situation fraught with uncertainty"; "everything was unstable following the coup"
• S: (adj) fluid, runny (characteristic of a fluid; capable of flowing and easily changing shape)
• similar to
• derivationally related form
• antonym
• S: (adj) fluent, fluid, liquid, smooth (smooth and unconstrained in movement) "a long, smooth stride"; "the fluid motion of a cat"; "the liquid grace of a ballerina"
• S: (adj) fluid, liquid (in cash or easily convertible to cash) "liquid (or fluid) assets"
• S: (adj) fluid, mobile (affording change (especially in social status)) "Britain is not a truly fluid society"; "upwardly mobile"
• similar to
• S: (adj) changeable, changeful (such that alteration is possible; having a marked tendency to change) "changeable behavior"; "changeable moods"; "changeable prices"
• antonym
• W: (adj) unchangeable [Indirect via changeable] (not changeable or subject to change) "a fixed and unchangeable part of the germ plasm"-Ashley Montagu; "the unchangeable seasons"; "one of the unchangeable facts of life"