If you have recently begun using your cellphone or computer to exchange text messages with people, you may have seen an unfamiliar string of letters sent by someone, and wondered what it means. When someone sends "SMH" to you in a text message, it could have a few different meanings, depending on the context.
Text Messaging Abbreviations
People often are pressed for time when they are exchanging text messages, and to help them speed their communication, they can use a variety of abbreviations to stand for longer phrases. For example, if you see "ROTFL," that means the person wants to say "Rolling on the floor laughing" in response to something hilarious.
When someone poses a question to you and you aren't sure of the answer or you need some time to think, you may physically scratch your head to indicate the thought processes. People often type "SMH" to indicate "Scratching My Head" in a text message to let someone else know that they are pondering the subject of discussion. You may need to wait a while to get the next text message, while the other person continues to think of what to write next.
If you are exchanging text messages with someone and receive a text with "SMH," examine the context to see if the person means "Shaking My Head." A person will express dismay by shaking her head when someone says or does something stupid. When you receive "SMH," it does not necessarily mean that your correspondent is saying that you did or said something stupid. The writer could be referring to someone else's actions that you are discussing.
Disappointment and Irritation
In some cases, the letters "SMH" in a text message are meant to stand for "Smack My Head." A person will write "SMH" to indicate that she is feeling so irritated or disappointed by something that someone has done or said, that the only response is to smack her head in irritation or frustration.