unprizable

From un- +‎ prizable.

unprizable (comparative more unprizable, superlative most unprizable)

1. (obsolete) Not prized or valued; without value; not worth capturing.
   • c. 1601–1602 (date written), William Shakespeare, “Twelfe Night, or What You Will”, in Mr. William Shakespeares Comedies, Histories, & Tragedies  (First Folio), London: Isaac Iaggard, and Ed Blount, published 1623, →OCLC, :

     A bawbling vessel was he captain of,
     For shallow draught and bulk unprizable;

2. (obsolete) Invaluable; whose value is beyond estimation.
   • 1625, Nicholas Breton, “A Quyet Woman”, in Characters and Essayes‎, Aberdeen: Edward Raban, page 45:

     Shee is a Pearle, that is vnprizable;

   • 1725, Henry Baker, “The Petition”, in Original Poems: Serious and Humourous‎, London: for the author, page 2:

     If in all your boundless Store
     A Blessing so unprizable there be,
     Crown whate’er you gave before
     With a true Friend, full of Sincerity:

• “unprizable”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC.