Possible Clues:

• Mars, spoils
• Debilitates
• Vitiates
• Diminishes in function ... or a hint to what's found in 17-, 23-, 49- and 59-Across
• Harms
• Mischief-maker with affectedness improves? Quite the opposite
• I am in short, enough of what spoils 31 acrosses
• Damages
• Hampers