Synonyms: wraithlike, shadowy
Definition: lacking in substance
Usage: strange fancies of unreal and shadowy worlds- W.A.Butler; dim shadowy forms; a wraithlike column of smoke
Similar words: insubstantial, unreal, unsubstantial
Definition: lacking material form or substance; unreal
Usage: as insubstantial as a dream; an insubstantial mirage on the horizon