| requisite(noun, adjective, right, condition, want) |
| need(noun, verb, work, charge, understanding) |
| prerequisite(noun, adjective, condition, want, need) |
| requirement(noun, understanding, right, condition, want) |
| obligation(noun, work, charge, right, concern) |
| necessity(noun, force, understanding, right, condition) |
| essential(noun, adjective, right, want, need) |
| condition(noun, need, essential, essence, basic) |
| imperative(noun, adjective, need, essential, obligation) |
| ought(noun, verb, work, charge, understanding) |
| necessary(noun, adjective, want, need, essential) |
| demand(noun, right, want, need, essential) |
| duty(noun, understanding, right, concern, care) |
| should(verb, consider, leave, allow, bear) |
| have(verb, bear, endure, want, need) |
| have to(verb, expression, idiom, phrasal verb, bear) |
| precondition(noun, condition, need, essential, certainty) |
| sine qua non(noun, expression, idiom, condition, need) |
| charge(noun, work, understanding, right, care) |
| indispensable(adjective, required) |