The Collaborative International Dictionary of English v.0.48:

Primal \Pri"mal\, a. [LL. primalis, fr. L. primus the first. See
   Prime, a.]
   First; primary; original; chief.
   [1913 Webster]

         It hath the primal eldest curse upon it. --Shak.
   [1913 Webster]

         The primal duties shine aloft like stars. --Wordsworth.
   [1913 Webster]

WordNet (r) 3.0 (2006):

primal
    adj 1: serving as an essential component; "a cardinal rule";
           "the central cause of the problem"; "an example that was
           fundamental to the argument"; "computers are fundamental
           to modern industrial structure" [syn: cardinal,
           central, fundamental, key, primal]
    2: having existed from the beginning; in an earliest or original
       stage or state; "aboriginal forests"; "primal eras before the
       appearance of life on earth"; "the forest primeval";
       "primordial matter"; "primordial forms of life" [syn:
       aboriginal, primal, primeval, primaeval,
       primordial]

Moby Thesaurus II by Grady Ward, 1.0:

154 Moby Thesaurus words for "primal":
   ab ovo, abecedarian, aboriginal, antenatal, arch, atavistic,
   austere, autochthonous, banner, bare, basal, basic, basilar,
   beginning, bodily, born, budding, capital, cardinal, central,
   champion, chaste, chief, coeval, congenital, connatal, connate,
   connatural, constituent, constitutional, constitutive, creative,
   crowning, crucial, dominant, elemental, elementary, embryonic,
   essential, fetal, first, focal, foremost, formative, foundational,
   fundamental, generative, genetic, germinal, gestatory, great, gut,
   headmost, hegemonic, hereditary, homely, homespun, homogeneous,
   in embryo, in its infancy, in ovo, in the blood, in the bud,
   inaugural, inborn, inbred, incarnate, inceptive, inchoate,
   inchoative, incipient, incunabular, indigenous, indivisible,
   infant, infantile, inherited, initial, initiative, initiatory,
   innate, instinctive, instinctual, introductory, inventive,
   irreducible, leading, magisterial, main, master, material, mere,
   monolithic, nascent, natal, native, native to, natural, natural to,
   of a piece, of the essence, organic, original, overruling,
   paramount, parturient, physical, plain, postnatal, predominant,
   preeminent, pregnant, prenatal, preponderant, prevailing, primary,
   prime, primeval, primitive, primogenial, primordial, principal,
   pristine, procreative, protogenic, pure, pure and simple, radical,
   ranking, rudimental, rudimentary, ruling, seminal, severe,
   simon-pure, simple, single, sovereign, spare, star, stark, stellar,
   substantial, substantive, supereminent, temperamental, topflight,
   unadorned, uncluttered, underlying, undifferenced,
   undifferentiated, uniform, ur