A strongman is a political leader who rules by force and runs an authoritarian regime or totalitarian regime. The term is often used interchangeably with "dictator" in the western world, but differs from a "warlord" and commonly lacks the negative connotations especially in some Eastern European and Central Asian countries.
A strongman is not necessarily always a formal head of state or head of government; sometimes journalists use the term to describe a military or political figure who exercises far more influence over the government than a local constitution allows. General Manuel Noriega, for example, was often dubbed the "Strongman of Panama" for the enormous amount of political power he exercised over Panama, despite the fact that he was not the formal president or prime minister of the state.
Similarly, not every discussion of "strong leadership" (or every promise to provide such) envisages rule by a strongman.