the.com/sanctimony
Virtue's costume, worn loudly so everyone notices you forgot the actual virtue.
means A showy, hollow display of moral superiority that has the appearance of holiness without the substance.
from From Latin sanctimonia, holiness, from sanctus, sacred — but somewhere along the way the sacredness fell off and only the performance stayed.
Hollow holinessOnce meant genuine sanctity, now strictly counterfeit.
Shakespeare's wordHe used it sincerely before it soured into sarcasm.
Sanctimonious cousinThe adjective is far more famous than the noun.