It's what you call someone after you push them into a bush or nearby shrub.
Jack: "Ah ha! BushMonkey!"
John: "ya bastard!"
Jack: "BUSH PUUUUUSH!"
a woman of the unusually hairy variety, expecially in the "nether" regions. ex. Madonna in her Playboy pictures.
Hey, yo, weasel that bitch was such a bushmonkey that it would take me all day, a compass, and a brushhog to find her frog.