1 Violation of established uses in Classical architecture.
2 Corruption of form. Abuses according to Palladio included brackets, consoles, or modillions supporting (or seeming to support) a major structural load, e.g. a column; broken or open-topped pediments; exaggerated overhangs of cornices; and rusticated or banded columns (see band). Perrault and others identified further abuses: pilasters and columns physically joined, especially at the corner of a building; coupled columns (which Perrault himself employed at the east front of the Louvre in Paris); distortion of metopes by making them wider and rectangular instead of square in abnormally large intercolumniations; omission of the bottom part of the Ionic abacus; Giant Orders instead of an assemblage of Orders; an inverted cavetto moulding joining the plinth under a column-base to the cornice of a pedestal; architrave-cornices (as in Hellenistic Ionic); and entablatures broken or interrupted immediately above a column. Through use many abuses have become acceptable aspects of Classicism.
Gwilt (1903);W. Papworth (1852)