coldness vs chilliness

coldness and chilliness both are nouns.

Word	Noun	Adjective	Verb	Adverb
coldness	Yes	No	No	No
chilliness	Yes	No	No	No

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

Other hyponyms of coldness include chill, gelidity, iciness, coolness, nip, frostiness, cool.

As nouns, coldness and chilliness are synonyms defined as:

Other synonyms of coldness include coolness, frigidity, frigidness, iciness.

coldness (noun)	chilliness (noun)
the absence of heat	the property of being moderately cold
a lack of affection or enthusiasm	a lack of affection or enthusiasm
the sensation produced by low temperatures