knuckled

from The Collaborative International Dictionary of English v.0.48

Knuckle \Knuc"kle\, v. i. [imp. & p. p. {Knuckled};; p. pr. &
   vb. n. {Knuckling}.]
   To yield; to submit; -- used with down, to, or under.
   [1913 Webster]

   {To knuckle to}.
   (a) To submit to in a contest; to yield to. [Colloq.] See {To
       knock under}, under {Knock}, v. i.
   (b) To apply one's self vigorously or earnestly to; as, to
       knuckle to work. [Colloq.]
       [1913 Webster]

from The Collaborative International Dictionary of English v.0.48

Knuckled \Knuc"kled\, a.
   Jointed. [Obs.] --Bacon.
   [1913 Webster]