unseizable

adj

1. That cannot be seized or grasped.

   “A large packet of 'Text Books'--left for that purpose by Norrish, if the truth were known-- whose covers were the same color as those of the 'Fruits', attracted Mr. Outram's attention, and he took off some of the brown paper wrapper, but found the goods unseizable.”

   “He eluded all pursuit, and his name--or at least the name he gave himself--was known all over the world, and inspired horror and terror everywhere, as being that of a legendary personage, a bogey, invisible and unseizable.”

   “For a moment she was lost in the pursuit of an unseizable clue--the explanation of this monstrous last perversity of fate.”