New Oxford American Dictionary
I have heard this word often. Most recently I read it in Michael J. Fox's book, Something Funny Happened on the Way to the Future, where the author uses the word to describe his brother.
In the past few weeks, I have been seeing this word a lot, since I have been relearning the German language with the help of Duolingo.com. I recommend the site. It is really fun. Well, in German, Mensch means person, Menschen means people. I have been familiar with this definition for many years, but I never really understood the meaning when used as part of the English language (as defined above). It is interesting to me that a word can be borrowed from another language and then have more meaning added to it.
Have you tried Duolingo yet?