The Oxford Thesaurus An A-Z Dictionary of Synonyms - theoreticaladj.

1) hypothetical, conjectural, speculative, untested, unproved, unproven, moot, putative, debatable, supposititious, suppositional: The theoretical trajectory will take it beyond Uranus. 2) impractical, unrealistic, pure, ideal, abstract, academic: The suggestion was purely theoretical, since we have no means of carrying it out.