| paramount(important, significant, original, serious, basic) |
| pivotal |
| powerful |
| prerequisite(important, capital, essential, critical, basic) |
| primal |
| prime(important, significant, original, serious, basic) |
| primordial(important, significant, original, basic, vital) |
| principal(important, original, serious, capital, basic) |
| required(important, capital, essential, critical, basic) |
| requisite(important, significant, capital, essential, critical) |
| rudimentary(adjective, important, significant, original, basic) |
| structural(important, significant, original, basic, vital) |
| substantive |
| substratal(important, significant, original, basic, vital) |
| substrative(important, significant, original, basic, vital) |
| supporting(important, significant, original, basic, vital) |
| sustaining(important, significant, original, basic, vital) |
| theoretical(important, significant, original, basic, vital) |
| underived(important, significant, original, basic, vital) |
| underlined(important, essential, critical, basic, fundamental) |