I would describe ~~windows~~ Office as a combination Spyware Malware. It actively collects data on you using obscure means, in an attempt to prevent you from knowing how it's collecting it. It will also actively change your settings without your knowledge. With recent updates I would even classify it as potentially adware as well, ~~since they mentioned adding advertisements to the start menu and explorer.~~ since they hard push their office products.

~~Honestly, with the fact that it also now force installs software against the users will on updates, the argument could be made that it's slipping into trojan territory as well, it's just lacking the backdoor access, but since they are hard pushing MS account authorization for login, I guess you don't really need a backdoor when if you wanted to you could just force a password change and be able to login via the native login system.~~

edit: I thought this post was based off MAS as in to activate windows, I just now realized it was MAS for office activation. I still think that the same applies, just not the trojan aspect. I have edited it to reflect it.