Green’s Dictionary of Slang

a general intensifier, completely, utterly; often as screaming funny.

1898		W.T. Goodge ‘The Great Aus. Adjective’ in Bulletin 11 Dec. 26: The ------ Government’s ------ ways Are screamin’ ------ funny.
1911		L. Stone Jonah 291: Screamin’ funny, ain’t it?
1929		(con. 1917–18) C. MacArthur War Bugs 210: Unquestionably he would have gone screaming, tittering nuts.
1951		E. Hemingway letter 5 Mar. in Baker Sel. Letters (1981) 721: How did they ever get a picture of a wide-eared jerk [...] to look that screaming tough.
1962		K. Williams Diaries 15 July 195: This feeling of living in an atmosphere of such wilful stupidity & wickedness that I was going screaming mad.
1977		S. Berkoff East in Decadence and Other Plays (1985) 57: Violent histories of battles too screaming delirious for verbal-mere-pub-splatter.