The Collaborative International Dictionary of English v.0.48:

Worm \Worm\, v. i. [imp. & p. p. Wormed; p. pr. & vb. n.
   Worming.]
   To work slowly, gradually, and secretly.
   [1913 Webster]

         When debates and fretting jealousy
         Did worm and work within you more and more,
         Your color faded.                        --Herbert.
   [1913 Webster]