1609, "one who studies and resolves cases of conscience," from Fr.
casuiste, from L.
casus (see
case (1)). Often in a sinister or contemptuous sense.
Casuistry is first attested 1725.
"Casuistry ... destroys, by distinctions and exceptions, all morality, and effaces the essential difference between right and wrong." [Bolingbroke, 1736]