| essential(noun, adjective, right, condition, important) |
| necessary(noun, adjective, important, want, need) |
| required(adjective, close, correct, exact, important) |
| indispensable(adjective, important, significant, original, essential) |
| imperative(noun, adjective, important, need, significant) |
| prerequisite(noun, adjective, condition, important, want) |
| necessity(noun, condition, want, need, essential) |
| requirement(noun, right, condition, want, need) |
| mandatory(adjective, significant, essential, basic, vital) |
| vital(adjective, important, significant, original, essential) |
| needful(adjective, important, significant, capital, essential) |
| compulsory(adjective, significant, essential, basic, vital) |
| obligatory(adjective, appropriate, proper, significant, suitable) |
| must(noun, adjective, right, condition, want) |
| needed(adjective, close, correct, exact, important) |
| condition(noun, need, essential, essence, basic) |
| need(noun, condition, want, essential, certainty) |
| demand(noun, right, want, need, essential) |
| fundamental(noun, adjective, important, need, significant) |
| proviso(noun, adjective, condition, essential, requirement) |