I don't think you are hacked, but the auto complete list is corrupt.
Go to https://outlook.live.com/mail/0/options/general/export and clear the suggested list by clicking the Clear data and Turn off button. Wait 24 hours and go back there to turn it back on. You can (and probably should) click the link download the data before clearing it.
Or, if its just your name that is goofy and only you see it, leave it.