/un hawrs"/ , v.t., unhorsed, unhorsing .
1. to cause to fall from a horse, as in battle; dislodge from the saddle: Sir Gawain unhorsed the strange knight.
2. to defeat; overcome; dislodge, as from a position or office: His vigorous campaign unhorsed his adversary.
[ 1350-1400; ME unhorsen. See UN- 2 , HORSE ]