The Collaborative International Dictionary
Counterproving
Counterprove \Coun`ter*prove"\ (koun`t?r-pr??v"), v. t. [imp. & p. p. Counterproved (-pr??vd"); p. pr. & vb. n. Counterproving.] To take a counter proof of, or a copy in reverse, by taking an impression directly from the face of an original. See Counter proof, under Counter.
Wiktionary
counterproving
vb. (present participle of counterprove English)