The prohibited practice of buying stock in a cash account and then selling it before it has been paid for is known as:

Kiting refers to the illegal practice of writing checks on accounts that do not have sufficient funds, usually to create the illusion of having more available cash. This is not directly related to stock trading practices but rather pertains to check fraud and is distinct from the concept of freeriding.

Churning is the practice of excessively buying and selling securities in a client's account to generate commissions for the broker, rather than to benefit the client’s investment strategy. While churning is unethical and illegal, it involves excessive trading rather than the act of buying and selling stock without paying for it, as in freeriding.

Front running is the unethical practice where a broker executes orders on a security for its own account while taking advantage of advance knowledge of pending orders from its customers. This is a different issue entirely, focusing on unethical behavior related to information asymmetry, not on the mechanics of payment in trading.