Inconstancy is a related term of liveliness.
As nouns the difference between inconstancy and liveliness
is that inconstancy is lack of constancy; lack of consistency in thought, emotion or action while liveliness is the quality of being lively; animation; energy.
inconstancy
English
Noun
(
inconstancies)
Lack of constancy; lack of consistency in thought, emotion or action.
-
liveliness
English
Noun
(-)
The quality of being lively; animation; energy.