Formal:
* Absurdités (plural noun): This is the most formal and neutral way to say "nonsense." It literally translates to "absurdities."
* Bêtise (feminine noun): This is another formal option that means "stupidity" or "foolishness."
Informal:
* Bêtises (plural noun): This is the informal version of "bêtise." It's often used to refer to silly or childish things.
* Imbécilité (feminine noun): This word is quite strong and means "idiocy" or "stupidity."
* Sottise (feminine noun): This is a more nuanced word that means "foolishness" or "silliness."
* Des bêtises (phrase): This means "nonsense" or "rubbish."
* C'est n'importe quoi (phrase): This is a very common and informal phrase that literally translates to "it's anything at all." It's a way of saying "that's ridiculous" or "that's nonsense."
* Des âneries (plural noun): This means "nonsense" or "rubbish," similar to "des bêtises."
The best way to choose the right word or phrase depends on the context and your relationship with the person you're talking to.