In this sense [appeasement] is seen as a policy of making one-sided concessions, often at the expense of third parties and with nothing offered in return except promises of better behaviour in the future, in a vain attempt to satisfy the aspirations of the aggressor states.
[...]
The most famous [...] of the appeasers was inevitably Neville Chamberlain. It was during his premiership (1937–40) that appeasement reached its climax with the Munich settlement of September 1938, by which Britain sought to avoid war over Czechoslovakia by agreeing to Nazi demands for the annexation of the German-speaking parts of that state [...].
[...]
Among anti-appeasers the name of Winston Churchill inevitably takes first place. [...] Churchill stands as the isolated prophet who consistently warned the government of the dangers posed by Nazi Germany and of the disaster to which the policy of appeasement would inevitably lead.

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