Theoretical
Part of speech: adjective
Definition: of or pertaining to theoretic studies (abstract, not empirical)
Example sentence: The research I have been doing - studying how foodstuffs yield energy in living cells - does not lead to the kind of knowledge that can be expected to give immediate practical benefits to mankind. If I have chosen this field of study, it was because I believed in its importance in spite of its theoretical character.
Pure
Part of speech: adverb
Definition: to a great extent or degree; extremely; exceedingly.
Part of speech: adjective
Definition: free of flaws or imperfections; unsulliedfree of foreign material or pollutantsfree of immoral behavior or qualities; cleanof a branch of science, done for its own sake instead of serving another branch of science.
Example sentence: A pure hand needs no glove to cover it.