pessimi exempli (pes-<<schwa>>-mI eg-zem-plI). [Latin] Hist. Of the worst example.

“Thus, to acquit a man of a crime because he had committed it under the influence of drink, or to allow any one to take benefit under a contract induced by his fraud, would be pessimi exempli, as tending to lead others to be dishonest or unfair in their dealings, or to be careless of their habits or their acts.” John Trayner, Trayner’s Latin Maxims 457 (4th ed. 1894).

[Blacks Law 8th]