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

1) basic, essential, elementary, fundamental, rudimental, primary, introductory, abecedarian, formative, first, initial, elemental, primal, seminal: The purpose of the course is provide students with a rudimentary knowledge of computer programming. 2) crude, coarse, unshaped, unfinished, imperfect, primitive, undeveloped, vestigial, embryonic, primordial, immature: These fish, which spend their lives in darkness, have only a rudimentary organ for an eye.