| basic(noun, adjective, characteristic, drop, part) |
| essential(noun, adjective, support, action, characteristic) |
| elementary(adjective, characteristic, simple, plain, pure) |
| primary(adjective, body, simple, plain, material) |
| organic(adjective, important, natural, animate, original) |
| elemental(adjective, body, simple, plain, material) |
| underlying(adjective, simple, plain, important, straightforward) |
| cardinal(noun, adjective, important, head, significant) |
| central(adjective, important, significant, original, essential) |
| intrinsic(adjective, characteristic, important, significant, natural) |
| necessary(noun, adjective, body, material, important) |
| principal(noun, adjective, body, material, important) |
| integral(noun, adjective, characteristic, part, body) |
| key(noun, adjective, important, head, significant) |
| radical(adjective, important, significant, original, essential) |
| rudimentary(adjective, simple, plain, important, head) |
| prime(adjective, body, material, pure, important) |
| basal(adjective, body, simple, plain, material) |
| crucial(adjective, important, significant, original, capital) |
| vital(adjective, body, material, important, significant) |