certain aspects or traits of a person or thing that reveal themselves, either occasionally or on a regular basis.
"It doesn't really surprise me that she said things to you. But don't take it personally. I mean, after all, she's generally a nice person, albeit a bit quirky at times. It's just the nature of the beast I guess."
by Polo May 1, 2006
A term used to describe or excuse the fact you're getting fucked in the ass and there's nothing you can do a about it.
Guy getting fucked:"What the fuck do you mean I have to work tonight, I haven't even gotten relieved yet?!"
Guy fucking you: "Well that's the nature of the beast."
by Lubrication&relaxation September 19, 2015