| inherent(adjective, essential, basic, absolute, fundamental) |
| initial(adjective, simple, straightforward, basic, fundamental) |
| innate(adjective, basic, absolute, fundamental, key) |
| integral(adjective, important, significant, original, essential) |
| introductory(adjective, simple, straightforward, basic, fundamental) |
| key(adjective, important, significant, original, essential) |
| main(adjective, original, essential, basic, absolute) |
| major(adjective, important, significant, original, essential) |
| material(adjective, basic, absolute, fundamental, key) |
| meat-and-potatoes(adjective, important, significant, fresh, original) |
| meat and potatoes(expression, adjective, idiom, simple, plain) |
| name of the game(expression, adjective, idiom, basic, absolute) |
| necessary(adjective, important, significant, original, essential) |
| nitty-gritty(adjective, original, basic, absolute, fundamental) |
| nub(adjective, original, basic, absolute, fundamental) |
| paramount(adjective, important, significant, original, essential) |
| perfect(adjective, basic, absolute, fundamental, key) |
| plain(adjective, simple, straightforward, basic, fundamental) |
| prefatory(adjective, simple, straightforward, basic, fundamental) |
| preliminary(adjective, simple, straightforward, basic, fundamental) |