There are no perfect rhymes for the word dullness.
The opposite of glitter is dullness.
dullness is how bright a color is, eg dull is very un-bright
The dullness of the day was very depressing compared to the sunshine they had last week.
Definition of mental dullness; describing your personality and mind set to be bland with no effort to create enlightenment. Eg: a person with a basic brain with not much character has mental dullness
Dullness
Dullness
Constantly uninteresting
Lethargic. No energy, sluggishness, slowness or dullness. (No get up and go)
sharpness Answer: Alert and active
The closest you can get to it is just 'dullness'
the antonym is dullness and spirtlessness.
The vividness or dullness of a color