| momentous(adjective, significant, essential, basic, vital) |
| mood(noun, quality, type, kind, character) |
| name of tune(noun, expression, idiom, quality, type) |
| nature of beast(noun, expression, idiom, quality, type) |
| necessary(adjective, essential, required, needed) |
| needed(adjective, significant, essential, basic, vital) |
| needful(adjective, significant, essential, basic, vital) |
| nitty-gritty(noun, adjective, quality, character, spirit) |
| nitty gritty(noun, expression, adjective, nature, quality) |
| nub(noun, adjective, quality, character, spirit) |
| nucleus(noun, quality, character, spirit, significance) |
| obligatory(adjective, significant, essential, basic, vital) |
| outlook(noun, quality, type, kind, character) |
| personality(noun, quality, type, kind, character) |
| pith(noun, quality, character, spirit, significance) |
| point(noun, quality, type, kind, character) |
| prerequisite(noun, adjective, significant, essential, basic) |
| pressing(adjective, significant, essential, basic, vital) |
| principle(noun, nature, quality, character, spirit) |
| property(noun, nature, quality, character, spirit) |