Defeat an Opponent in Every Single Game
Puzzle 5 of Running a Marathon Pack
Question is: Defeat an Opponent in Every Single Game
and the answer is: WHITEWASH
Word Meaning:
WHITEWASH — (uncountable) A mixture of a powdered mineral substance (often slaked lime (containing calcium hydroxide), chalk (calcium carbonate), or both) and water which is used for painting surfaces such as fences and walls bright white.
Definitions from Wiktionary.