| cardinal(adjective, important, significant, original, essential) |
| central(adjective, important, significant, original, essential) |
| clear(adjective, simple, straightforward, basic, fundamental) |
| cold(adjective, basic, absolute, fundamental, key) |
| complete(adjective, basic, absolute, fundamental, key) |
| congenital(adjective, basic, absolute, fundamental, key) |
| connate(adjective, basic, absolute, fundamental, key) |
| constitutional(adjective, important, significant, original, essential) |
| constitutive(adjective, important, significant, original, basic) |
| crucial(adjective, important, significant, original, essential) |
| deep-seated(adjective, original, essential, basic, absolute) |
| duck soup(expression, adjective, simple, straightforward, basic) |
| easy(adjective, simple, straightforward, basic, fundamental) |
| facile(adjective, simple, straightforward, basic, fundamental) |
| first(adjective, rough, important, significant, fresh) |
| grass-roots(adjective, important, significant, original, essential) |
| ideal(adjective, basic, absolute, fundamental, key) |
| inborn(adjective, basic, absolute, fundamental, key) |
| inbred(adjective, basic, absolute, fundamental, key) |
| indispensable(adjective, important, significant, original, essential) |