A very drunk person who can't stand up straight. Derived from the last name Hasselhoff from actor David Hasselhoff, because of his drunken behavior that was seen all over the web. The two parts of his last name being "Hassel and "Hoff" are changed to "Boozen" and "Slob" then combined together and that was how the name was formed.
Did you watch that video of David Hasselhoff wasted off his rocking chair last night.
Yeah he was a complete Boozenslob.