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.
"Larger than life" is an idiom, so there isn't an idiom for it.
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.
"To be" is not an idiom - it's a verb.
Coinage could be accurately described as neology.The recent coinage of the word redonkulous is suspect.
It is a idiom.