Now that I have your attention, let me remind & instill in your brain that there is no such thing as a bad teacher. A teacher can never be bad at his/her profession. If he/she teaches bad, he/she would be a fantastic mentor; if he/she is a poor guide, he/she would be a fantastic tutor; so on…. But if you are looking for something like a synonym or an apt word to dub your teacher who behaved like he/she had a tiff with his/her spouse the previous night of your submission D-day, you could go with simply “IMPERSON!”
Now this is a made-up word & I am not intending to be Shakespeare by creating words. This can be used among your friends so that you can vent your ire out without being a contemptible person.
Coming to the point, to be an imperson, you got to be lazy. And by lazy, I mean, procrastinator, imbecile & every other word in the dictionary which means ignoramus. Only thing to say is, come submission day, you will have to blame for everything caused by you to the student in question. And to successfully be called as an imperson, give that student few negative pointers & voila, for the rest of his/her life, you will become an imperson for him/her. And to be sure about the coveted consequences, try actually following the rules & stereotypes of the college like, for example, no correction of experiments on the submission day. Right? Tell me how you score.