What is the origin of the idiom "sharp practice" and when to use it?

The origin of the idiom "sharp practice" can be traced to the business world of the 18th century Industrial Revolution period. During this era of expanding markets, some merchants engaged in cunning tactics like deception to secure an advantage over competitors. These individuals were referred to as "sharp" due to their crafty business methods and the term "sharp practice" was used to describe their methods. This phrase is often used to describe behavior that is self-serving and lacks in good faith or ethics.