"shoot inserted into another plant," late 15c. alteration of Middle English graff (late 14c.), from Old French graife "grafting knife, carving tool, stylus," from Latin graphium "stylus," from Greek grapheion "stylus," from graphein "to write" (see -graphy). So called probably on resemblance of a stylus to the pencil-shaped shoots used in grafting. The terminal -t- in the English word is not explained. Surgical sense is from 1871.

"corruption," 1865, perhaps 1859, American English, perhaps from graft (1) via British slang sense of "one's occupation" (1853), which seems to be from the word's original sense of "digging" (see graft, n.1).