So "Post-truth" describes an era when the truth doesn't matter, but instead people's feelings/fears and what is often called "common sense" - although there's nothing wrong with common sense, the idea is that it has such a high position in society now that even when something is proven to be incorrect, people don't care.
Some examples: For what it's worth, I think I've only heard "post-truth" used with the term "era", so that's how I'll use it.
- The prevalence of fake news in the 2016 election cycle is an example of the true beginning of the "post truth" era
- People's preference for hearing only views which agree with their own contributes to the growth of the "post truth" era
Xenophobia is literally the fear of difference. It is most often used to describe people who are fearful of other cultures and the people from those cultures. Xenophobia is different to racism, in that someone who is xenophobic doesn't necessarily care about your skin colour or nationality (though it can mean that as well), but is usually fearful of cultural practices which are different to their own, often viewing them as a threat.
- Many people believe that xenophobia is the reason behind the US' recent travel ban.
- Xenophobia was seen to be a huge part of Donald Trump's campaign success
- Those who believe in tolerance and plurality are often disliked by those with xenophobic tendencies