also monkeyshines, "monkeyish behavior, tricks, pranks, antics," U.S. slang, 1832 (in the "Jim Crow" song), from monkey (n.) + shine (n.) "a caper, trick" (1835), from an American English slang sense perhaps related to the expression cut a shine "make a fine impression" (1819); see slang senses under shine (n.). For sense of the whole word, compare Old French singerie "disreputable behavior," from singe "monkey, ape."
Also compare monkey business"foolish or deceitful conduct," attested by 1858; one early source from England describes it as a "native Indian term," but the source might be that alluded to in, among other places, this contemporary account given by a professional strongman:
After Gravesend I came up to London, and went and played the monkey at the Bower Saloon. It was the first time I had done it. There was all the monkey business, jumping over tables and chairs, and all mischievous things; and there was climbing up trees, and up two perpendicular ropes. I was dressed in a monkey's dress; it's made of some their hearth rugs; and my face was painted. It's very difficult to paint a monkey's face. I've a great knack that way, and can always manage anything of that sort. [Mayhew, "London Labour and the London Poor," 1861]