Adjective
Lacking in matter or substance; visionary; chimerical.
Source: Webster's dictionaryConstitutional rights should not be frittered away by arguments so technical and unsubstantial. Louis Brandeis
But when we sit together, close,' said Bernard, ‘we melt into each other with phrases. We are edged with mist. We make an unsubstantial territory. Virginia Woolf
Do we, holding that the gods exist, deceive ourselves with unsubstantial dreams and lies, while random careless chance and change alone control the world. Euripides
as insubstantial as a dream Source: Internet
an insubstantial mirage on the horizon Source: Internet
Theology was, however, "rather unsubstantial fodder" for d'Alembert. Source: Internet