Is hangry a real word? According to Collins Dictionary it means to be angry as a result of being hungry, but it seems far-fetched.
If it's in a dictionary, especially one with professional full-time editors, the chances are it's a real word. Of these kind of dictionaries, I can only find it in Collins, and their webpage notes it's "humorous" and also added from a recent suggestion:
Collins also say:
You can find it used on Twitter, although often with an explanation it means hungry and angry.
The earliest hangry I found with this definition in Usenet is in rec.games.trivia from 1996:
So it appears to be used as humorous slang, and you should only use it as such.
Edit: It's now been added to Oxford Dictionaries, which adds to its wordocrity.
It is slang, but it's become commonly accepted slang...though not commonly used. According to the Urban Dictionary, it means:
I found several other sites which used similar definitions...and in fact, it's the most logical definition I could think of.