Definition of "rascally"

He was speedily reassured, and with a large, white, rascally grin, and a glance at his charge, seemed to take me into partnership in his exalted trust.

1899 February, Joseph Conrad, “The Heart of Darkness”, in Blackwood’s Edinburgh Magazine, volume CLXV, number M, New York, N.Y.: The Leonard Scott Publishing Company, […], part I, page 205

“The horse would be part of the estate. What do they care for my bets? As likely as not they would not run him at all. My chief creditor is, unhappily, my most bitter enemy—a rascally fellow, Sam Brewer, whom I was once compelled to horse-whip on Newmarket Heath. Do you suppose that he would try to save me?”

1927 March 5, Arthur Conan Doyle, “The Adventure of Shoscombe Old Place”, in The Case-Book of Sherlock Holmes, London: John Murray, […], published June 1927 (May 1952 printing), page 298

“I hope,” said Jones, “you don’t intend to leave me in this condition.” “Indeed but I shall,” said the other. “Then,” said Jones, “you have used me rascally, and I will not pay you a farthing.”

1749, Henry Fielding, The History of Tom Jones, a Foundling, volumes (please specify |volume=I to VI), London: A[ndrew] Millar, […]