theory vs theoretic

theory is a noun but theoretic is not a noun.

Word	Noun	Adjective	Verb	Adverb
theory	Yes	No	No	No
theoretic	No	Yes	No	No

theory (noun)	theoretic (noun)
a well-substantiated explanation of some aspect of the natural world; an organized system of accepted knowledge that applies in a variety of circumstances to explain a specific set of phenomena
a tentative insight into the natural world; a concept that is not yet verified but that if true would explain certain facts or phenomena
a belief that can guide behavior

theory (adjective)	theoretic (adjective)
	concerned primarily with theories or hypotheses rather than practical considerations