Dictionary
im•pugn
Pronunciation: (im-pyOOn'), [key]—
v.t.
1. to challenge as false (another's statements, motives, etc.); cast doubt upon.
2. Archaic.to assail (a person) by words or arguments; vilify.
3. Obs.to attack (a person) physically.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.