The quality of being dull; lack of brightness, interest, or vitality.

A lack of mental sharpness or acuity.

नीरसता

English Usage: The dullness of the sky made the day feel gloomy.

Hindi Usage: आसमान की नीरसता ने दिन को उदास बना दिया।

A state of being unexciting or monotonous.

उबाऊपन

English Usage: The dullness of the lecture made it hard to stay awake.

Hindi Usage: व्याख्यान की उबाऊपन के कारण जागना मुश्किल था।