1846 A. J. W. Morrison tr. H. Ritter IV. xii. vi. 428 With this doctrine of the unmentionableness of God, the belief that in his nature he is unknowable, is naturally connected.
1917 25 Oct. 450/2 Of Baudelaire,..all the world is now made to know that his unmentionableness was mainly Stevenson's ‘inappropriate talk’.
2003 Aug. 168 A thoroughly ‘wicked and vile’ plan, also linked to the unmentionableness of sodomy.