Today's lesson is a quick one! It may not even warrant a lesson of its own, but because I find that I repeatedly have to look this Internet-based acronym up, am taking the unnecessary plunge.
Let's get to it! SMH means "shaking my head." The Young People like to add it to their messages, Tweets, and status updates as a means to show disapproval.
For example: "Ugh, I can't believe the final Hunger Games novel is split into two movies! smh"
or: "Ugh, I can't believe this girl doesn't know her homonyms! #smdh"
It's possible the Young People didn't roll their eyes at that news, but I did. "SMH" can be used for seemingly trivial misfortunes or serious political issues. The acronym is generally used in all lowercase letters.
I hope I saved you 30 seconds!
smh, Urban Dictionary