a. (UN-1 7 b.)

1

  In recent use esp. of postal matter, as in quot. 1862.

2

1843.  Carlyle, Past & Pr. II. xvii. Fix thyself in Dandybood, undeliverable: it is thy doom.

3

1862.  Trollope, N. Amer., II. 388. The task of returning to their writers undelivered and undeliverable letters.

4