Despite its common usage, I found that grunties has more definitions than almost any other word. I have listed as many generalized categories as I can find with its source cited. If you would like to add definitions please do so, I simply recommend that you include a valid source for it.

1.) A fantastical people who live in East London 100 years in future. They are a happy (if shallow) people who work hard, eat well, and spend their evenings enjoying the carnal pleasures of the "electrical hearth", a machine which "dazzles the eyes while stimulating the baser glands." From the book War Drums on the Maitland by Emily Chesley. Interesting perspective for a book written in 1896. Of course the fact of the matter is that 1996 has already happened. Really! Who could possibly imagine a society held captive at night by a glowing electrical box? That's absurd!

2.) A belief of thought held by some that "it's okay if you like spam. it's also okay if you don't like spam. just don't try to cram your personal feelings about spam down somebody else's throat. and if ya do, grunties to you. and that kinda says it all, ya know?" (from the Church of the Most Holy Grunties)

3.) Another name for "The Saucy Nun" (from The Constitution of the Cambridge University Science Fiction Society)

4.) According to the cast of Monty Python, it is one of the most offensive words one could say. However, it is not nearly as offensive as the words "Wankle-Rotary Engine"

5.) A British euphemism for testicles.

6.) Slang for little girls. "Gathers the young grunts and grunties..." from Campfire Story by K'larz.

7.) Apparently a type of noise, "Hazy morse code blips and electronic grunties originate from the direction of east north-east".