Plain old stupid Something or someone who fits into the category of normal stupidity. Plain and old merrily describe the word stupid. SMH is a popular online acronym that teens and young adults love to type into their social media posts or in text messages to express the same physical body language of shaking their head in disappointment, disagreement and/or disbelief. It might be in response to somebody else's behavior, an event that took place, or the state of a situation. Regardless of why, the only response you can muster is to shake your head. Example 1 As an example, let's say that a Twitter user tweeted something about how their favorite sports team just lost a game. The could add "smh" at the end of the tweet to further express their disappointment: "The Purple Eagles totally should've won that game! They had it when Pizzaburghenshire made that shot!! Smh." Example 2 In another example, let's say that your teenage son replied with nothing but a simple "smh" text message after you messaged him to say that there's absolutely no way you can lend him the car on Saturday for a meet up with his anime fan club friends. He's clearly disappointed: You: "I need the car this Saturday, so you'll have to find another way to get to your weekly Nakuro Dragonflame X meeting." Your son: "SMH" SMH is used when someone did or said something that you don’t approve of whatsoever. Just like your friend Debby, when she says she loves her boyfriend but then she goes and sleeps over at another dudes’ house. SMH, Debby. If you need a little more emphasis, go with SMDH, “shaking my damn head.”