Green’s Dictionary of Slang

plausy adj.

also plausey
[SE plausible]

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

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.
[UK]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.
[Ire](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.