| imperative(need, essential, requirement, prerequisite, essentiality) |
| in a dilemma |
| in a pickle |
| in a predicament |
| in the middle |
| indispensability(need, essential, requirement, prerequisite, inevitability) |
| inevitability(need, essential, requirement, prerequisite, essentiality) |
| inexorableness(need, essential, requirement, prerequisite, essentiality) |
| life or death(expression, idiom, need, essential, requirement) |
| must(need, essential, requirement, prerequisite, inevitability) |
| necessary(need, essential, requirement, prerequisite, inevitability) |
| need(essential, requirement, prerequisite, inevitability, essentiality) |
| needfulness(need, essential, requirement, prerequisite, inevitability) |
| no alternative(noun, expression, need, essential, requirement) |
| obligation(need, essential, requirement, prerequisite, essentiality) |
| pinch(need, essential, requirement, prerequisite, essentiality) |
| precondition(need, essential, requirement, prerequisite, essentiality) |
| prerequisite(need, essential, requirement, essentiality) |
| privation(need, essential, requirement, prerequisite, essentiality) |
| requirement(need, essential, prerequisite, essentiality) |