A person who is ashamed to admit he/she has no knowledge about a question asked so tries to hide his/her ignorance by inanely prattling on, dancing around the obvious and useful answer; "I don't know", which would allow you to get on with your day, i.e. go find someone who knows what the hell they are talking about.
You: Good Lord! My ignorant boss just refuses to say "I DON"T KNOW" so I had to stand there listening to his worthless bullshit for ten minutes. Finally I just walked away and left him jibber jabbering away. He's probably still talking for all I know.
Sympathetic coworker: Yep, he's a windbag alright. By the way, I overheard your question and the answer is yes.