1) Someone that feels compelled to spell check and point out everyone's spelling and grammar errors is labelled a "mskye"
2) a walking f7 button
3) When you correct someone on a extremely minor spelling error you are "msyking" them.
4) If you have made a seemingly inconsequential error in spelling or grammar and someone points it you have been "mskyed"
eg 1. "woahhh did you see what she how she forgot to put the apostrophe in the word "they're" Mannnnnn you better msyke that chick."
eg 2: "i pointed out that she should so know by now that "definitely" as not spelt "definately". She's been m-syked."