The Collaborative International Dictionary of English v.0.48:

Rankle \Ran"kle\ (r[a^][ng]"k'l), v. i. [imp. & p. p. Rankled
   (-k'ld); p. pr. & vb. n. Rankling (-kl[i^]ng).] [From
   Rank, a.]
   1. To become, or be, rank; to grow rank or strong; to be
      inflamed; to fester; -- used literally and figuratively.
      [1913 Webster]

            A malady that burns and rankles inward. --Rowe.
      [1913 Webster]

            This would have left a rankling wound in the hearts
            of the people.                        --Burke.
      [1913 Webster]

   2. To produce a festering or inflamed effect; to cause a
      sore; -- used literally and figuratively; as, a splinter
      rankles in the flesh; the words rankled in his bosom.
      [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

27 Moby Thesaurus words for "rankled":
   acerb, acerbate, acerbic, acid, acidic, acidulent, acidulous,
   acrimonious, bitter, burning, caustic, choleric, embittered,
   haunted, mindful, nagged, obsessed, plagued, rancorous,
   remembering, resentful, resenting, sore, splenetic, stewing,
   unable to forget, virulent