a. (UN-1 7 b.)
In frequent use from c. 1880.
1533. Bellenden, Livy, V. xv. (S.T.S.), II. 199. At þe fute of þe montanis, quhilkis stude sa hie aganis him þat þai apperit vnclymabil.
1827. Lincoln & Lincolnshire Cabinet, 9. The almost unclim[b]able street which, as before stated, runs directly up the hill.
1892. Rider Haggard, Nada the Lily, 211. It was of no great height, and yet unclimbable, for the sides of it were sheer.