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

Their life seems to be one long series of impulsions, fostered and sustained by the extreme lability of their emotions.

From Project Gutenberg

And this, in turn, may be regarded as but a manifestation of the process of survival by lability rather than by stability.

From Project Gutenberg