| compelling(adjective, significant, essential, basic, vital) |
| complexion(noun, quality, type, kind, character) |
| compulsory(adjective, significant, essential, basic, vital) |
| constitution(noun, nature, quality, type, kind) |
| core(noun, quality, character, spirit, significance) |
| crux(noun, quality, character, spirit, significance) |
| de rigueur(expression, adjective, significant, essential, basic) |
| decisive(adjective, significant, essential, basic, vital) |
| element(noun, quality, character, spirit, significance) |
| elementary(adjective, significant, essential, basic, vital) |
| entity(noun, nature, quality, character, spirit) |
| essence(noun, quality, type, kind, character) |
| essentia(noun, nature, quality, character, spirit) |
| essential(noun, adjective, significant, heart, basic) |
| essentiality(noun, nature, quality, type, kind) |
| exigent(adjective, significant, essential, basic, vital) |
| expedient(adjective, significant, essential, basic, vital) |
| features(noun, quality, type, kind, character) |
| fiber(noun, quality, character, spirit, significance) |
| form(noun, nature, quality, character, spirit) |