As used in this chapter, unfair competition shall mean and include any unlawful, unfair or fraudulent business act or practice and unfair, deceptive, untrue or misleading advertising and any act prohibited by Chapter 1 (commencing with Section 17500) of Part 3 of Division 7 of the Business and Professions Code. Any person who engages, has engaged, or proposes to engage in unfair competition may be enjoined in any court of competent jurisdiction.