levity > define

noun

• Feeling an inappropriate lack of seriousness.
• A manner lacking seriousness. .

• (n.) Lack of gravity and earnestness in deportment or character; trifling gayety; frivolity; sportiveness; vanity.
• (n.) The quality of weighing less than something else of equal bulk; relative lightness, especially as shown by rising through or floating upon, a contiguous substance; buoyancy; -- opposed to gravity.
• (n.) Lack of steadiness or constancy; disposition to change; fickleness; volatility.