verbal diarrhoea, n. — Green’s Dictionary of Slang

verbal diarrhoea n.

[note late 17C–late 19C fig. use of SE diarrhoea, an excessive flow of words etc.]

excessive talk, esp. when meaningless, pointless and irritating to the hearer.

1947		C. Willingham End as a Man (1952) 138: You’ve got verbal diarrhoea, with these journals, notes, speeches, and things.
1951		D. Stivens Jimmy Brockett 163: When he got verbal diarrhoea I always knew to look out for something.
1979		D. Maitland Breaking Out 257: Billy suffered from chronic verbal diarrhoea.
1999		G. Seal Lingo 2: Although mostly taken for granted, the importance of the vernacular in everyday life is apparent from the number of Lingoisms describing or referring to it [...] earbashing; yabber; yacking; verbal diarrhoea.
2003		McGill Reed Dict. of N.Z. Sl.