a large, verbivorous animal which is able to think underwater for long periods of time
We are aware of the difficulties of proving a negative, such as the statement "There is not a hipphilosamus in my living room, " and that even if you show us a photograph of your living room with no hipphilosamus in it, and adduce as well a tape recording on which no hipphilosamus tread is discernible, how can we be sure that the photograph has not been retouched, the tape cunningly altered, or that both do not either pre- or postdate the arrival of the hipphilosamus? That large, verbivorous animal which is able to think underwater for long periods of time?
Someone who metaphorically or physically sprays others. (Commonly when hippos shit they wave their tail while shitting. This creates a majestic spray that grotesquely colors it's surroundings. Someone who constantly runs their mouth, always gossips, or sprays when they talk can be categorized as a hipposhit.)
The hypothetical man (often a sinistercharacter who decided not to go to boot camp) that is doing your girlfriend/wife while you are on deployment overseas.
Ain't no use in goin home,
Jody's got your girl and gone.
Ain't no use in goin back,
Jody's got your Cadillac,
Ain't no use in feeling blue,
Jody's took your checkbook too.