Shaking my head, commonly abbreviated as SMH, is a type of chat and Internet slang for user expression. It often effectively signals someone’s disappointment or disgust for something, or other similar negative emotional reactions.
Like other typical acronyms, SMH developed from user patterns where the keyboards, touch screens and interfaces of the devices led people to try to type things more quickly and take a lot of lexical shortcuts. Using the contraction SMH, someone can effectively express their emotions through text messaging or other venues in just three letters, as opposed to 13 letters and two spaces.
SMH was first added to the Urban Dictionary in 2004 with a meaning that’s identical to the initialism’s current meaning. Nobody knows where the phrase came from. Still, it was probably conceived around the same time as the phrase “facepalm,” a similar internet expression that was first uploaded to the Urban Dictionary the same month as SMH