Ungirthed

(ppl.) a. [UN-¹ 8, 9.] Not provided with, or secured by, a girth. Also fig.

1628.  Feltham, Resolves, II. ix. 24. Many times, honest Industry spends a man more, then the vngirthed Solaces of a sensuall Libertine.

1813.  Scott, Rokeby, VI. note. The major … clapped the saddle, ungirthed as it was, upon his horse.

1901.  Westm. Gaz., 13 Aug., 8/2. If … there had been a saddle thrown upon the pony, it was ungirthed.