Green’s Dictionary of Slang

(Anglo-Irish) smooth-tongued, overly polite, apparently weak.

1884		R.G. Thomsett Kohât, Kuram and Khost 173: I hoped General Roberts and his Politicals would not pin their faith too much to this plausy Governor.
1935		Punch CLXXXVIII 47/3: If you only was to hear the plausy talk them lassies had in the shop, an’ they winkin’ an’ blinkin’ at me at the same time.
1943		(con. 1850s) G.A. Little Malachi Horan Remembers 29: After bedding the horse, and the women had got shut of the plausey talk, Kitty found herself sitting down.