dinky vs insignificant

dinky is a noun but insignificant is not a noun.

Word	Noun	Adjective	Verb	Adverb
dinky	Yes	Yes	No	No
insignificant	No	Yes	No	No

As adjectives, dinky and insignificant are synonyms defined as:

dinky (noun)	insignificant (noun)
a small locomotive

dinky (adjective)	insignificant (adjective)
(British informal) pretty and neat	devoid of importance, meaning, or force
small and unimpressive	signifying nothing
	of little importance or influence or power; of minor status
	small and unimpressive