An Etymological Dictionary of Astronomy and Astrophysics

1. To ward off attack from; guard against assault or injury.
   

   2. To maintain by argument, evidence, etc.; uphold (Dictionary.com).

Etymology (EN): From → de- “from, away,” + -fendere “to strike, push,” → offend.

Etymology (PE): Padâfandidan, from padâfand, from prefix pad- “contrary to; against; opposing,” → counter-,

• âfand “strife, war,” → offend.