Sorry - it won’t wash.
The Urban Dictionary -
http://www.urbandictionary.com/define.php?term=grundle
And The Medical Dictionary -
http://medical-dictionary.thefreedictionary.com/Grundle
say otherwise.
A word can have more than one meaning. I was born in 1971, and that is my favorite video game of all time. That is how I see the word. You may see the word differently, and that is fine.