| grass-roots(adjective, important, significant, original, essential) |
| heavy(adjective, important, essential, critical, basic) |
| imperative(adjective, important, essential, critical, basic) |
| indispensable(adjective, important, significant, original, essential) |
| integral(adjective, important, significant, original, essential) |
| intrinsic(adjective, important, significant, original, essential) |
| key(adjective, important, significant, original, essential) |
| life-or-death(adjective, important, significant, essential, critical) |
| major(adjective, important, significant, original, essential) |
| meaningful(adjective, important, essential, critical, fundamental) |
| name(adjective, important, significant, essential, critical) |
| name-of-the-game(adjective, important, significant, essential, critical) |
| necessary(adjective, important, significant, original, essential) |
| needed(adjective, important, essential, critical, basic) |
| nitty-gritty(adjective, important, essential, critical, basic) |
| original(adjective, important, significant, fresh, essential) |
| paramount(adjective, important, significant, original, essential) |
| prerequisite(adjective, important, essential, critical, basic) |
| primary(adjective, base, important, significant, last) |
| prime(adjective, important, significant, original, essential) |