Green’s Dictionary of Slang

(US campus) to copy, to cheat in an examination; thus skinning n. and adj.

1835		J. Todd Student’s Manual 115: Should you allow yourself to think of going into the recitation-room, and there trust to ‘skinning,’ as it is called in some colleges, [...] or ‘mouthing it,’ as in others [DA].
1849		Yale Literary Mag. XV. 81: Never skin a lesson which it requires any ability to learn.
1852		C.A. Bristed Five Years in an Eng. University 381: Classical men were continually tempted to ‘skin’ (copy) the solutions of these examples.
1856		B.H. Hall College Words (rev. edn) 430: skin [...] to obtain a knowledge of a lesson by hearing it read by another; also, to borrow another’s ideas and present them as one’s own; to plagiarize; to become possessed of information in an examination or a recitation by unfair or secret means.
1871		L.H. Bagg Four Years at Yale 622: The object of these modes of skinning, is to cram up the lesson, bit by bit, keeping just ahead of the part which is being recited, in expectation of being one’s self called up.
1895		J.S. Wood Yale Yarns 231: He was certain sure it was a skinning paper!
1900		E.H. Babbitt ‘College Words and Phrases’ in DN II:i 60: skin, v. To cheat, in general, especially in examination [...] To copy an answer in examination or an exercise in classwork.