Gossip; particularly where information gets around that is not supposed to. "Loose lips sink ships" was a famous saying in World War I.
LOOPZ - LOOR - LOOREY - LOOS - LOOSE - LOOT - LOP - LOP-L - LOP-P - LOP-V
"LOOSE LIPS." Abbreviations.com. STANDS4 LLC, 2015. Web. 27 Nov. 2015. <http://www.abbreviations.com/LOOSE%20LIPS>.