The quality of being improper; unfitness or unsuitableness to character, time place, or circumstances; as, impropriety of behavior or manners.
That which is improper; an unsuitable or improper act, or an inaccurate use of language.
Liberty, Familiarity, Indecorum
Anxiety, Propriety, Sobriety, Society, Variety
Impropriety in Spanish is Impropiedad