Refers to a person's mental state of being calm, collected, and not easily flustered. Often used in phrases like 落ち着きがある (to be composed) or 落ち着きを失う (to lose one's composure).
Describes a state of being stable, settled, or not fluctuating. Can apply to objects, situations, or abstract conditions. Common in expressions like 落ち着きがない (restless, fidgety) or 落ち着きのあるデザイン (a stable, settled design).