Stuff and nonsense
Rubbish, nonsense. Also used, although less often in recent years, as an exclamation of incredulity.
In this little term, stuff doesn't have any especial meaning beyond its normal usage - it just means, well, stuff, and is used merely as an intensifier for the word nonsense. The term is sometimes written as 'stuff and non-sense' to distinguish the 'rubbish' meaning from the exclamatory one.
It is first recorded in print in The Times, June 1827, in a parliamentary debate:
"He [Mr. Pitt] had at once to declare, that all notions of concerting and of dictating to the King in the exercise of his prerogative, was mere stuff and nonsense."
The use of the singular 'was' in that sentence indicates that 'stuff and nonsense' was expressed as a phrase rather than as two separate words.