Xenophobia is the fear or dislike of strangers or unknown things. Xenophobia can also mean the fear of trying new things, but it is usually the fear of differences between people. Xenophobia may be about foreign things or people, or just the attitudes of a group towards other groups. It may increase because of immigration. Apparently, xenophobia has always existed. Even the Ancient Greeks believed that barbarians (non-Greeks) were naturally meant to be enslaved.