ThMk

This is the accronym you accidentally think is an accronym, but is really an abbreviated version of thank you. If you are like me, you were texted this and spent 20 minutes searching google to try to crack the code so that you would seem cool and trendy to whoever sent it to you. And then you stumbled upon this definition, and now you're both relieved and embarrassed that it took you this long to figure that out.