lightness vs silliness

lightness and silliness both are nouns.

Word	Noun	Adjective	Verb	Adverb
lightness	Yes	No	No	No
silliness	Yes	No	No	No

As nouns, silliness is a hypernym of lightness; that is, silliness is a word with a broader meaning than lightness:

Other hypernyms of lightness include giddiness.

lightness (noun)	silliness (noun)
the trait of being lighthearted and frivolous	a ludicrous folly
the visual effect of illumination on objects or scenes as created in pictures	an impulsive scatterbrained manner
the property of being comparatively small in weight
having a light color
the gracefulness of a person or animal that is quick and nimble
a feeling of joy and pride