( abbr HUAC )
a committee established in 1938 by the US House of Representatives to investigate activities that might threaten the American government and people. It became famous in the 1950s when, under the influence of Senator Joseph McCarthy , it accused many innocent people of supporting Communism. It was responsible for several of these being sent to prison. In 1969 the committee changed its name to the House Committee on Internal Security, and in 1975 it was brought to an end.