lability

[ luh-bil-i-tee, ley- ]

noun

1. the fact or quality of being likely to change:

   The lability of the neuromuscular system during physical therapy was measured in muscle force and reaction times.

2. Chemistry, Biochemistry. the ability or likelihood of a substance or compound to change or break down easily, rapidly, or continually:

   It was found that the degree of lability varies considerably with different amido-aldehydes.

3. Psychiatry. the unregulated or unstable state of emotions or mood, characterized by exaggerated affective expression:

   They were concerned about his emotional lability, from flaring anger one moment to maudlin sentimentality the next.

Word History and Origins

Origin of lability¹

First recorded in 1550–60 in a different sense; equivalent to Latin lābili(s) “sliding, slipping” ( labile ( def ) ) + -tās -ty ²( def )

Example Sentences

"We show that this sexual parasitism trait is ancestral for all deep-sea anglerfishes and appears to have evolved as a synergistic combination of ancestral lability in the genetic basis of the adaptive immune system and body size dimorphism," Brownstein says, noting that female anglerfishes do not reject males as foreign bodies, allowing fusion.

From Science Daily

Emotional lability is a common symptom of prion disease.

From Science Magazine

A play about loss, loneliness and the hope of connection, “Primary Trust,” which runs through July 2 at the Roundabout’s Laura Pels Theater, is also a shrewd and gentle vehicle for Harper’s particular gifts — vulnerability, thoughtfulness, emotional lability.

From New York Times

In his book “Why We Sleep,” the neuroscientist Matthew Walker half-jokes that dreams are a time when everyone on Earth becomes “flagrantly psychotic,” experiencing hallucinations, delusions, disorientation, emotional lability and amnesia.

From New York Times

The boredom, frustration, mortification, warmth, impulsiveness, lability, silliness, bewilderment and capacity to forgive.

From Washington Post