linguistics vs retroflex

linguistics is a noun but retroflex is not a noun.

Word	Noun	Adjective	Verb	Adverb
linguistics	Yes	No	No	No
retroflex	No	Yes	Yes	No

linguistics (noun)	retroflex (noun)
the scientific study of language
the humanistic study of language and literature

linguistics (adjective)	retroflex (adjective)
	bent or curved backward
	pronounced with the tip of the tongue turned back toward the hard palate

linguistics (verb)	retroflex (verb)
	articulate (a consonant) with the tongue curled back against the palate
	bend or turn backward