adjective
1.
Synonyms: imperceptible , impalpable, imponderable, inappreciable, indiscernible, insensible, invisible, unapparent, unappreciable, unobservable
Related Word: rare, tenuous, thin; slender, slight; aerial, aeriform, airy, ethereal; eluding, elusive, evading, evasive; touchless
Antonyms: tangible
2.
Synonyms: elusive , elusory, evasive