KMSO

KMSO stands for "knocked my socks off," which is another way to say that you are really surprised or impressed. It is typically used in text messages and online when space for characters is limited.

You probably won't see KMSO used much since the "knock my socks off" phrase is primarily used by old people that wouldn't think to send it as the KMSO acronym. But if you do receive it, it will probably be in reference to being surprised, like when a "slacker" can play an instrument really well or when a movie gives you all the "feels."