| constitutive(important, original, serious, basic, prime) |
| necessary(adjective, body, material, important, significant) |
| original(adjective, simple, important, natural, straightforward) |
| aboriginal(adjective, pure) |
| basilar |
| indispensable(adjective, important, significant, original, essential) |
| key(adjective, lead, important, head, significant) |
| lowermost(adjective, base, last, bottom) |
| lowest(adjective, easy, base, last, basic) |
| main(adjective, lead, head, master, essential) |
| major(adjective, lead, head, master, boss) |
| minimal(adjective, slightest, littlest) |
| nethermost(adjective, base, last, bottom) |
| primitive(adjective, body, simple, plain, material) |
| primordial(adjective, important, original, basic, vital) |
| principal(adjective, lead, head, master, boss) |
| substantial |
| undermost(adjective, base, last, bottom) |
| white(adjective, pure) |
| abecedarian(simple, straightforward, basic, fundamental, uncomplicated) |