The word "victory" refers to the success or triumph achieved in a struggle or competition. Thus, to find its antonym, we need a word that conveys the opposite meaning, which in this case would be a lack of success or a loss.
War: This word refers to an armed conflict and is neither aligned with the concept of victory nor directly its opposite.
Peace: A state of tranquility or freedom from conflict, which is not the direct opposite of "victory."
Defeat: Meaning to lose or fail in achieving victory, making it the direct opposite.
Failure: Generally refers to a lack of success but is broader than the specific context of losing a competition or battle compared to "defeat."