Source : Webster's Revised Unabridged Dictionary (1913)

Thumbed \Thumbed\, a.
   1. Having thumbs.

   2. Soiled by handling.

Thumb \Thumb\, v. t. [imp. & p. p. {Thumbed}; p. pr. & vb. n.
   {Thumbing}.]
   1. To handle awkwardly. --Johnson.

   2. To play with the thumbs, or with the thumbs and fingers;
      as, to thumb over a tune.

   3. To soil or wear with the thumb or the fingers; to soil, or
      wear out, by frequent handling; also, to cover with the
      thumb; as, to thumb the touch-hole of a cannon.

            He gravely informed the enemy that all his cards had
            been thumbed to pieces, and begged them to let him
            have a few more packs.                --Macaulay.

Source : WordNet®

thumbed
     adj : (of pages) worn or soiled by thumb and fingers by frequent
           handling or turning; "well-thumbed pages of the
           dictionary"