| Abbreviation | Definition |
|---|---|
| MJ | Mike Joseph |
| MJ | Missy Jo |
| MJ | Monkey Jehovah |
| MJ | Morty Jeff |
| MJD | Mean Joe Dirt |
| MK | Mary Katherine |
| MK | Mary Kay |
| MK | Megan Kirkpatrick |
| MK | Missionary's Kid |
| MM | Merry Mary |
| MM | Michael Myers |
| MM | Mighty Max |
| MMM | Mellow Man Max |
| MN | Middle Name |
| MNIZ | My Name is Zygmunt |
| Mohd | Mohammad |
| Mohd | Muhammad |
| MOHIT | Millions Of Happiness In Thou |
| MORGAN | Mostly Orgasmic Really Gorgeous And Naughty |
| MOS | Man Of Steel |