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