A complete idiot that has self-designated authority in a work environment to micromanage and police others. This person has self-proclaimed self-importance and thus self-authoritity to bully others according to loose definitions of office policies. This person feels insecure by nature, has probably been molested as a child, and feels threatened by others due to lack of any relevant talent or skill relating to thier actual job. Weasel.
Him: I just busted the pseudovisor spying over my shoulder to see what I was doing! WTF!?!
Her: What a douchebag! He should focus on his own lack of talent and skill and get his ass to work!
Him: No shit, Sherlock. But he IS my PSEUDOVISOR!
The person left in charge when the boss is gone. Has no real authority, just added responsibilities. Can be a nice person or a nasty one.
Coworker: Man I love it when Bob is pseudovisor; he always brings in donuts. I wish he was our real supervisor.