| provision(noun, condition, arrangement, essential, obligation) |
| needed(adjective, important, significant, essential, critical) |
| needful(adjective, set, important, significant, capital) |
| vital(adjective, set, right, important, significant) |
| called for(verb, expression, adjective, phrasal verb, essential) |
| clause(noun, condition, requirement, qualification, provision) |
| desideratum(noun, want, need, essential, certainty) |
| wanted(adjective, important, significant, capital, essential) |
| basic(noun, adjective, important, want, significant) |
| expedient(adjective, significant, essential, basic, vital) |
| fundamental(noun, adjective, important, need, significant) |
| important(adjective, essential, critical, vital, fundamental) |
| necessitous(adjective, important, capital, essential, vital) |
| specification(noun, condition, arrangement, obligation, requirement) |
| want(noun, need, essential, certainty, basic) |
| arrangement(noun, condition, essential, requirement, qualification) |
| catch |
| compulsory(adjective, set, significant, essential, basic) |
| constraint(noun, obligation, requirement) |
| escape clause(expression, idiom, qualification) |