| call(need, essential, requirement, prerequisite, essentiality) |
| cause(need, essential, requirement, prerequisite, essentiality) |
| cellular(material, natural, basic, living, functional) |
| claim(noun, need, essential, requirement, prerequisite) |
| clear and distinct(expression, idiom) |
| clear as day(expression, idiom) |
| closet |
| coal-and-ice(important, essential, critical, basic, fundamental) |
| coerce |
| cogent(clear, sound, reasonable, sensible, rational) |
| coherent(clear, sound, reasonable, sensible, rational) |
| comfort station |
| commonsensical(clear, sound, reasonable, sensible, rational) |
| compulsion(noun, want, need, essential, certainty) |
| congruent(clear, sound, reasonable, sensible, rational) |
| consequent(clear, sound, reasonable, sensible, rational) |
| consistent(clear, sound, reasonable, sensible, rational) |
| conspicuous(significant, vital, imperative) |
| constitutional(adjective, body, material, important, significant) |
| constitutive(important, original, capital, essential, critical) |