Source : Webster's Revised Unabridged Dictionary (1913)

Labile \La"bile\, a. [L. labilis apt to slip, fr. labi to slip.]
   Liable to slip, err, fall, or apostatize. [Obs.] --Cheyne.

Source : WordNet®

labile
     adj 1: open to change; liable to change; "an emotionally labile
            person"
     2: (chemistry, physics, biology) readily undergoing change or
        breakdown