A venial sin must always be some particular act. Now it is not easy to specify and put one's finger on the particular act, whereby a man, once poor, but now making money fast and eagerly, "exceeds his proper measure," as St Thomas puts it. Like every thing else in the Middle Ages, differences of class, marked by differences of dress, were more fixed and immutable than with us. Sumptuary laws restrained the low-born from donning the habiliments proper to the nobility. Sumptuary laws are not yet quite dead. A University would take it in ill part for a Commoner to go about in a Master's gown. A civilian would not be received in society, who persisted in wearing the uniform of a field-marshal. St Thomas would apparently take such uppishness and assumption for a venial sin.
Of God and His Creatures: 3.130