a substance that has no fixed shape and yields easily to external pressure; a liquid or gas
noun
Examples:
• Drink plenty of fluids when you have a fever to stay hydrated.
• Brake fluid should be checked regularly to ensure safe operation of the vehicle.
capable of flowing freely; smoothly adaptable
adjective
Examples:
• Her movements on stage were fluid and graceful.
• The company needs a fluid approach to adapt to market changes.