1645. Milton, Tetrach., Wks. 1851, IV. 228. He … permitted by accident the evil of them who divorc’t against the laws intention undiscoverably.
1680. Cotton, Compl. Gamester (ed. 2), 12. How neatly and undiscoverably he managed his tricks.
1892. Zangwill, Bow Mystery, 171. To assassinate secretly, mysteriously, unintelligibly, undiscoverably.
