Noun

(en noun)

Excessive or superfluous expenditure of money.

Prodigality as in extravagance of anger, love, expression, imagination, or demands.

:They spared nothing in obtaining extravagances for each other. Everything was lavish and wildly in excess. They were in love!

*

*:A great bargain also had been the excellent Axminster carpet which covered the floor; as, again, the arm-chair in which Bunting now sat forward, staring into the dull, small fire. In fact, that arm-chair had been an extravagance of Mrs. Bunting. She had wanted her husband to be comfortable after the day's work was done, and she had paid thirty-seven shillings for the chair.

Noun

(wikipedia simplicity)

The quality or state of being simple, unmixed, or uncompounded; as, the simplicity of metals or of earths.

The quality or state of being not complex, or of consisting of few parts; as, the simplicity of a machine.

Artlessness of mind; freedom from cunning or duplicity; lack of acuteness and sagacity.

Freedom from artificial ornament, pretentious style, or luxury; plainness; as, simplicity of dress, of style, or of language; simplicity of diet; simplicity of life.

Freedom from subtlety or abstruseness; clearness; as, the simplicity of a doctrine; the simplicity of an explanation or a demonstration.

Freedom from complication; efficiency.

*{{quote-magazine, date=2013-08-03, volume=408, issue=8847, magazine=(The Economist)

, title= Boundary problems , passage=Economics is a messy discipline: too fluid to be a science, too rigorous to be an art. Perhaps it is fitting that economists’ most-used metric, gross domestic product (GDP), is a tangle too. GDP measures the total value of output in an economic territory. Its apparent simplicity explains why it is scrutinised down to tenths of a percentage point every month.}}

Weakness of intellect; silliness; folly.

(rare) An act or instance of foolishness.

*, II.31:

*:speaking of the great simplicity we commit, in leaving yong children under the government and charge of their fathers and parents.