Slander or gossip, comes to mind. But it seems both too obvious and a stretch.
Naughty tongue = slander or gossip
SUN = the british tabloid?
Hit 2 birds - Arguably hurts the gossipper, but brings down the gossippee
The secret = the truth, which, if revealed, hurts the gossipper if the gossip was not true, or the gossippee if it was
blackjack
flooble's webmaster puzzle