Self-control or inhibition was the process of not acting on one's emotions. Lack of self-control around anger was colloquially referred to as "losing one's temper".
Vulcans greatly valued self-control and the general belief among them was that if they failed to be extremely inhibited, they would become dangerous to society and unable to use logic. One exception was the V'tosh ka'tur, who felt they could be logical and not dangerous without controlling all their emotions. (ENT: "Fusion")