Play Old Harry Meaning
(idiomatic) To play the devil; to make mischief.
Example: Blenkiron and I have been moving in the best circles as skilled American engineers who are going to play Old Harry with the British on the Tigris. â€” John Buchan, "Greenmantle", 1916.
I distinguish five more general classes: but I am far from equally happy about all of them. They are, however, quite enough to play Old Harry with two fetishes which I admit to an inclination to play Old Harry with, viz. (1) the true/false fetish, (2) the value/fact fetish. J. L. Austin, How to do things with words, Oxford 1962.