What does the term 'appeasement' mean?
GIving back what Germany had lost in the treaty of Versailles. e.g Hitler and Chamberlain. Chamberlain appeased Hitler by giving him part of Czechoslovakia.
It was difficult for countries to negotiate within the League of Nations, so this was developed to help countries to negotiate rather than use aggression against each other.
Churchill was not a believer in appeasement as he thought that Hitles demands were irrrational and that if you gave him something it wuol never be enough, and he would want more.
The policy was tried in 1930's to try to prevent Germany and Italy from going to war to meet their objectives.