19th century US. Probably an alteration of British dialect scaddle (“to run off in a fright”), from the adjective scaddle (“wild, timid, skittish”), from Middle English scathel, skadylle (“harmful, fierce, wild”), of Scandinavian origin; akin to Old Norse skaði (“harm”). Possibly related to the Greek σκέδασις (skedasis, “scattering”), σκεδασμός (skedasmos, “dispersion”). (US) Possibly related to scud or scat.
- 1897 Hunter, Robert, and Charles Morris (editors), Universal Dictionary of the English Language, v4, p4291: "Etym. doubtful; perhaps allied to scud. To betake one's self hurriedly to flight; to run away as in a panic; to fly in terror. (A word of American origin.)"
- “Skedaddle”, World Wide Words, Michael Quinion, 7 Feb. 2004.