silliness vs lightness

silliness and lightness both are nouns.

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

As nouns, lightness is a hyponym of silliness; that is, lightness is a word with a more specific, narrower meaning than silliness:

Other hyponyms of silliness include lightsomeness.

silliness (noun)	lightness (noun)
a ludicrous folly	the trait of being lighthearted and frivolous
an impulsive scatterbrained manner	the visual effect of illumination on objects or scenes as created in pictures
	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