Origin of labile
French, from Middle French, prone to err, from Late Latin labilis, from Latin labi to slip — more at sleep
First Known Use: 1603
Medical Definition of labile
: readily or frequently changing: asa: readily or continually undergoing chemical, physical, or biological change or breakdown <a labile antigen>b: characterized by wide fluctuations (as in blood pressure or glucose tolerance) <labile hypertension> <labile diabetes>c: emotionally unstable
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