la·bile
ˈlā-ˌbī(-ə)l 
-bəl
-bəl
1
: readily or continually undergoing chemical, physical, or biological change or breakdown : unstable
a labile mineral
2
: readily open to change
… has so labile a face that some of her scenes … rock with emotion.—
Manny Farber
Manny Farber
plural -es
: the quality or state of being labile
believe that a fall in population level … might enhance evolutionary lability—N. E. Collias & C. H. Southwick
N. E. Collias & C. H. Southwick
Did you know?
Labile was borrowed into English from French and can be traced back (by way of Middle French labile, meaning "prone to err") to the Latin verb labi, meaning "to slip or fall." Indeed, the first sense of labile in English was "prone to slip, err, or lapse," but that use is now obsolete. Other labi descendants in English include collapse, elapse, and prolapse, as well as lapse itself.
Examples of labile in a Sentence
Recent Examples on the Web
Patrick R. Crowley, Artforum, 1 Mar. 2026
The astonishing Laanstra-Corn does not play Hedvig purely as an innocent; there’s something as dangerous and emotionally labile in her shocked face as there is in Gregers’s explosive outbursts.
—Helen Shaw, New Yorker, 18 Sep. 2025
The mob is aroused and labile; the lumpy cops have no control, over the situation or over themselves.
—James Parker, The Atlantic, 12 Oct. 2024
Then the therapist could spend several minutes establishing a safe rapport with the patient while waiting for the memory to enter a labile state during the reconsolidation-updating window.
—Bj Casey, Scientific American, 14 May 2024
There was something kinetic, something labile in his air.
—Kevin Barry, The New Yorker, 8 Apr. 2024
Amid this high level of acting skill, Lindsey stood out with her wonderfully convincing gestures and facial expressions, filling out the character of the more labile younger sister with captivating verisimilitude.
—Jeremy Yudkin, BostonGlobe.com, 17 July 2023
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Adjective
While traditional facelifts merely tighten the skin in a superficial manner, deep-plane procedures can now reorganize the underlying structure of the face, repositioning muscles, fat pads, and ligaments in a labile system of roving features.
—Patrick R. Crowley, Artforum, 1 Mar. 2026
The astonishing Laanstra-Corn does not play Hedvig purely as an innocent; there’s something as dangerous and emotionally labile in her shocked face as there is in Gregers’s explosive outbursts.
—Helen Shaw, New Yorker, 18 Sep. 2025
The mob is aroused and labile; the lumpy cops have no control, over the situation or over themselves.
—James Parker, The Atlantic, 12 Oct. 2024
Then the therapist could spend several minutes establishing a safe rapport with the patient while waiting for the memory to enter a labile state during the reconsolidation-updating window.
—Bj Casey, Scientific American, 14 May 2024
There was something kinetic, something labile in his air.
—Kevin Barry, The New Yorker, 8 Apr. 2024
Amid this high level of acting skill, Lindsey stood out with her wonderfully convincing gestures and facial expressions, filling out the character of the more labile younger sister with captivating verisimilitude.
—Jeremy Yudkin, BostonGlobe.com, 17 July 2023
Cite this Entry
“Labile.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/labile. Accessed 10 Jun. 2026.
Copy CitationMedical Definition
: readily or frequently changing: as
a
: 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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