The Only Use

licentious
in
Pride and Prejudice
(Edited)

And it is the more to be lamented, because there is reason to suppose as my dear Charlotte informs me, that this licentiousness of behaviour in your daughter has proceeded from a faulty degree of indulgence; though, at the same time, for the consolation of yourself and Mrs. Bennet, I am inclined to think that her own disposition must be naturally bad, or she could not be guilty of such an enormity, at so early an age.
p. 281.9

licentiousness = degree of unacceptable sexual behavior

Definitions:

(1) (licentious)
of socially unacceptable sexual behavior
(2) (meaning too rare to warrant focus)
Less commonly in old literature, licentious can mean to ignore normal conventions -- especially of grammar or writing style