Tell the truth and run.

[yum-yum] {interj.}, {informal} - Used usually by or to children, to […]

[yuo] A usually deliberate typo of "you"

[Yuppie Food Coupons] Twenty dollar bills from an ATM.

[YW] "you're welcome"

[z00t] Also "zoot"-bastardization of "w00t"

[zero hour] {n.} 1. The exact time when an attack or […]

[zero in on] {v.} 1. To adjust a gun so that […]

[zig] "Cigarette".

[zip one's lip] See: [BUTTON ONE'S LIP].