Lability: The state or quality of being labile: susceptible to change, error or instability. From the Latin labilis meaning prone to slip, from labi meaning to slip. See also: Labile. From Healthy Resources 10 Rheumatoid Arthritis SymptomsHigh-Risk Myelofibrosis: Treatment Options10 Ways to Take Control of Your Migraine Featured Centers What Are the Best PsA Treatments for You?Understanding Biologics 10 Things People With Depression Wish You Knew