Green’s Dictionary of Slang

rubbish! nonsense!

1913		A. Lunn Harrovians 32: Tosh, you needn’t pretend you like it.
1916		‘New Church’ Times 29 May (2006) 91/1: Northcliffe, my Northcliffe, / I own I said ‘Tosh.’.
1920		Jewish Monitor (Ft Worth-Dallas, TX) 13 Aug. 1/2: ‘Love — tush!’ yelled Weinberg. [...] ‘Bah!’ he exploded angrily.