The term 'Cause of Ruin' can be broken down into four crossword solutions: UNDOING (7 letters), CURSE (5 letters), BANE (4 letters), and SCOURGE (7 letters). All of these words refer to something that can cause destruction or ruin. UNDOING is an action that reverses the effects of something, while CURSE is a powerful word or phrase that is said to bring bad luck or misfortune. BANE is something that causes harm or ruin, and SCOURGE is a severe punishment or affliction. Together, these words represent different ways in which something can be ruined or destroyed.