| obligatory(adjective, significant, essential, basic, vital) |
| prerequisite(adjective, significant, essential, basic, vital) |
| pressing(adjective, significant, essential, basic, vital) |
| quintessential(adjective, significant, essential, basic, vital) |
| required(adjective, significant, essential, basic, vital) |
| requisite(adjective, significant, essential, basic, vital) |
| specified(adjective, significant, essential, basic, vital) |
| unavoidable(adjective, significant, essential, basic, vital) |
| urgent(adjective, significant, essential, basic, vital) |
| wanted(adjective, significant, essential, basic, vital) |
| basic(adjective, significant, essential, vital, fundamental) |
| behooving |
| bottom line(expression, fundamental, decisive, imperative) |
| bounden(adjective, necessary, required, obligatory, conclusive) |
| cardinal(adjective, significant, essential, basic, vital) |
| chargeable |
| compliant(adjective, obedient, conscientious, well-behaved) |
| conclusive(adjective, necessary, required, obligatory) |
| conscientious(adjective, obedient, well-behaved) |
| counted upon(expression, adjective, necessary, required, obligatory) |