Stuff and nonsense
Definition 1 of 1
Pro Tip 1/3British Origin
Originally from British English, so it's understood best by British speakers or those familiar with British English. 
You believe he has a secret fortune? That's just stuff and nonsense!
Pro Tip 2/3Dismissive Tone
Conveys a strong rejection or disbelief in what is being discussed; it's dismissive and sometimes sarcastic. 
Claiming you've been to the moon is complete stuff and nonsense!
Pro Tip 3/3Informal Use
It's informal, often used in casual conversation among friends or in literature for character dialogue. 
The children talking of fairies is all stuff and nonsense.