doubty

From Middle English douti, douty, equivalent to doubt +‎ -y.

doubty (comparative more doubty, superlative most doubty)

1. (obsolete) Dubious, doubtful.
   • c. 1506, Stephen Hawes, “4 [The Tower of Doctrine]”, in The historie of graunde Amoure and la bell Pucel:

     That treated well, of a full noble story
     Of the doubty waye, to the tower perillous
     Howe a noble knight, shoulde winne the victory
     Of many a serpent, fowle and odious

By confusion with doubt.

doubty (comparative more doubty, superlative most doubty)

1. Obsolete form of doughty.
   • 1601, C[aius] Plinius Secundus [i.e., Pliny the Elder], “[Book VII.] XLIII.”, in Philemon Holland, transl., The Historie of the World. Commonly Called, The Naturall Historie of C. Plinius Secundus. […], 1st tome, London: […] Adam Islip, published 1635, →OCLC, page 178:

     he thereto aimed, namely, to be a most doubty and hardy warrior, an excellent orator, a right valiant captaine and commander

   • [1661, Thomas Blount, “Synonima's”, in Glossographia:

     So, stout, hardy, valiant, doubty, couragious, adventurous, all comprehended under the Latin word (fortis).]

• James A. H. Murray [et al.], editors (1884–1928), “Doubty, a.”, in A New English Dictionary on Historical Principles (Oxford English Dictionary), volumes III (D–E), London: Clarendon Press, →OCLC, page 618.