a. (UN-1 7 b.)
1847. C. Brontë, J. Eyre, xxi. Unimpressionable natures are not so soon softened.
1850. Thackeray, Pendennis, xv. Ah! what mad desires dashing up against some rock of obstruction or indifference, and flung back again from the unimpressionable granite!
1884. E. Yates, Recoll., II. 201. [He] was … as unimpressionable as an oyster.
