Someone who steps well within your personal space to carry on a conversation. Used to work with a guy who would walk next to me while talking and constantly bump into me. I also stopped a guy mid-sentence once and hung a paper towel from my safety glasses in order to let him know that when he got excited he would spittle the crap out of me.
This is CABL.com posting #188031. Tiny Link: cabl.co/mW4V