Although the word Fridle is a word it's not in the dictionary.
Not all words are in the dictionary and even when a word is made up recently it can still be an actual word but not be in the dictionary.
The word Fridle is a South Pacific word for a big, fat, stupid, and rich north American person.
Also another definition of the word Fridle is a new england version of a southern fiddle.
So while it may not be in the official dictionary the word Fridle is still an actual word that has a meaning and some people will know what you're talking about when you mention the word Fridle.
Even for some words that are in the dictionary some people may not know all the words.
You can find many words in the dictionary but not every word will be in the dictionary.