tininess vs diminutiveness

tininess and diminutiveness both are nouns.

Word	Noun	Adjective	Verb	Adverb
tininess	Yes	No	No	No
diminutiveness	Yes	No	No	No

As nouns, tininess and diminutiveness are synonyms defined as:

Other synonyms of tininess include minuteness, petiteness, weeness.

tininess (noun)	diminutiveness (noun)
the property of being very small in size	the property of being very small in size