"Ridonk" is an adjective referring to something so ridiculous it's beyond ridiculous. So "ridonkulous" is also a word.
Madame L guessed these meanings from the context of something she was reading, but looked it up in the Urban Dictionary to be sure.
(Warning: If you're offended by offensive language, don't bother to look up this word, or any word, in the Urban Dictionary. Trust Madame L.)
(Here's where Madame L read the word "ridonk" first. Again, don't follow the link if you're offended by offensive language and/or ideas. Yes, in this case, it's not just the language, but the very ideas [ideas about weight and women's bodies], that offend Madame L's and many of her readers' delicate sensibilities.)