An idiom is a phrase that seems to be nonsense until you know the definition. Redonkulous is a slang word.
Silly, ridiculous, reDONKulous.
rotate, revolve, revolution, redonkulous.
Redonkulous is something that is unbelievable sounds funny. And Ratatouille sounds pretty funny.
Idiom is correct.
what is a idiom about a cat
In an attempt to sound more intelligent, the bumbling speaker looked more like an imbecile using words incorrectly.
"To be" is not an idiom - it's a verb.
An idiom misuse is to use and idiom in a wrong way that doesn't make sense.
The idiom "apple shiner" means the teacher's pet.
"Larger than life" is an idiom, so there isn't an idiom for it.
Coinage could be accurately described as neology.The recent coinage of the word redonkulous is suspect.
It is a idiom.