Synonyms for Unsubstantially:

adv.

•immaterially (adverb)
conceptually, Impalpably, imponderably, intangibly, supernaturally, theoretically, spiritually, abstractly, Imaginarily, Ethereally, Immaterially.
•lightly (adverb)
Ethereally.
•unsubstantially (adverb)
vacuously, vacantly, insignificantly, emptily, Spectrally.

adv

•immaterially (adverb)
conceptually, Impalpably, imponderably, intangibly, supernaturally, theoretically, spiritually, abstractly, Imaginarily, Ethereally, Immaterially.
•lightly (adverb)
Ethereally.
•unsubstantially (adverb)
vacuously, vacantly, insignificantly, emptily, Spectrally.