| Solution | Length | |
|---|---|---|
| 3 letters | ||
| sap | 3 | |
| key | 3 | |
| 4 letters | ||
| rule | 4 | |
| sill | 4 | |
| core | 4 | |
| tone | 4 | |
| soul | 4 | |
| root | 4 | |
| quid | 4 | |
| pure | 4 | |
| seat | 4 | |
| 5 letters | ||
| stuff | 5 | |
| legal | 5 | |
| stark | 5 | |
| aeiou | 5 | |
| prime | 5 | |
| vital | 5 | |
| basal | 5 | |
| basic | 5 | |
| spare | 5 | |
| 6 letters | ||
| lawful | 6 | |
| staple | 6 | |
| primal | 6 | |
| simple | 6 | |
| rooted | 6 | |
| single | 6 | |
| spirit | 6 | |
| severe | 6 | |
| 7 letters | ||
| theorem | 7 | |
| natural | 7 | |
| uniform | 7 | |
| virtual | 7 | |
| primary | 7 | |
| Radicat | 7 | |
| precept | 7 | |
| radical | 7 | |
| seminal | 7 | |
| organic | 7 | |
| central | 7 | |
| 8 letters | ||
| rudiment | 8 | |
| pristine | 8 | |
| pregnant | 8 | |
| original | 8 | |
| ultimate | 8 | |
| standard | 8 | |
| primeval | 8 | |
| quiddity | 8 | |
| prenatal | 8 | |
| cardinal | 8 | |
| integral | 8 | |
| 9 letters | ||
| unadorned | 9 | |
| essential | 9 | |
| elemental | 9 | |
| important | 9 | |
| principle | 9 | |
| substance | 9 | |
| primitive | 9 | |
| 10 letters | ||
| UNDERLYING | 10 | |
| legitimate | 10 | |
| SUBSTRATUM | 10 | |
| simon-pure | 10 | |
| primordial | 10 | |
| 11 letters | ||
| Rock bottom | 11 | |
| rudimentary | 11 | |
| SUBSTANTIVE | 11 | |
| procreative | 11 | |
| terra firma | 11 | |
| preparatory | 11 | |
| UNCLUTTERED | 11 | |
| SUBSTANTIAL | 11 | |
| 12 letters | ||
| SINE QUA NON | 12 | |
| underpinning | 12 | |
| quintessence | 12 | |
| substructure | 12 | |
| 13 letters | ||
| indispensable | 13 | |
| turning point | 13 | |
| 14 letters | ||
| understructure | 14 | |
| CONSTITUTIONAL | 14 | |
| 15 letters | ||
| meatandpotatoes | 15 | |
| 16 letters | ||
| undifferentiated | 16 | |