| baseless | unsubstantial, lacking a foundation |
| fat | hefty, substantial, full-bodied |
| froth | insubstantial thing, empty moment |
| good | rich, wealthy, substantial |
| hollow | empty, wanting, insubstantial |
| incorporal | incorporeal, insubstantial, immaterial |
| insubstantial | lacking substance, imaginary, unreal |
| ponderous | weighty, substantial, profound |
| relative | pertinent, relevant, substantial |
| round | heavy, substantial |
| self-substantial | using substance from one's own body |
| shade | shadow, unreal image, unsubstantial semblance |
| slight | light, insubstantial, lacking solidity |
| starved | meagre, insubstantial, wanting |
| substantial | effective, thorough, forceful |
| substantial | real, of substance, not imaginary |
| toy | flimsy being, insubstantial thing |
| trivial | slight, poor, insubstantial |
| unreputed | insignificant, inconspicuous, insubstantial |
| unsubstantial | lacking in material substance, intangible |