lightness

noun

1. (uncountable)the condition of being illuminated

   “Well, darkness has a hunger that's insatiable and lightness has a call that's hard to hear.”

2. (uncountable)the relative whiteness or transparency of a colour
3. (countable)The product of being illuminated.
4. (uncountable)The state of having little (or less) weight, or little force.

   “The unique chassis design is largely the secret of the lightness of the locomotive.”

5. (uncountable)Agility of movement.
6. (uncountable)Freedom from worry.

   “In the lightness of my heart I sang catches of songs as my horse gayly bore me along the well-remembered road.”

7. (uncountable)Levity, frivolity; inconsistency.

   “Seneca […] accounts it a filthy lightness in men, every day to lay new foundations of their life, but who doth otherwise?”

   “And if the sudden and unannounced arrival of Miss Melhuish at "The Turrets" contained any element of surprise for him, his habitual imperturbability enabled him to pass it off with disarming lightness.”