Esperanto Dictionary is a helpful browser extension which will supposedly translate Esperanto words into your native language (or vice versa). However, it has been found to be an adware that will attempt to commandeer your browser search and homepage. This adware will display unwanted ads sending you to malicious websites to get money from you or infect your computer further. It may also monitor your browsing activities and prevent you from changing your settings back.
Esperanto Dictionary is usually installed through bundled software without you knowing. You have to remove it immediately.