repugnant (adj.)

late 14c., "contrary, contradictory," from Old French repugnant "contradictory, opposing" or directly from Latin repugnantem (nominative repugnans), present participle of repugnare "to resist, fight back, oppose; disagree, be incompatible," from re- "back" (see re-) + pugnare "to fight" (from PIE root *peuk- "to prick"). Meaning "distasteful, objectionable" is from 1777.