I've told whole lies
With a half smile
Another play on words, it describes how our narrater has lied, but isn’t completely fine with it.
The half smile could also be a turn of phrase intended to create a physical image of duplicity, or being “two-faced, in the listener’s mind. (it may help to think back to Harvey Dent, a.k.a. two-face, from Batman, to further stimulate the imagination.)
To help improve the meaning of these lyrics, visit “Cheerleader” by St. Vincent Lyrics and leave a comment on the lyrics box