tiny vs diminutive

tiny is not a noun while diminutive is a noun.

Word	Noun	Adjective	Verb	Adverb
tiny	No	Yes	No	No
diminutive	Yes	Yes	No	No

As adjectives, tiny and diminutive are synonyms defined as:

Other synonyms of tiny include bantam, flyspeck, lilliputian, midget, petite.

tiny (noun)	diminutive (noun)
	a word that is formed with a suffix (such as -let or -kin) to indicate smallness

tiny (adjective)	diminutive (adjective)
very small	very small