Origin of skedaddlepopularized in military slang of Civil War period: probably a fanciful formation
intransitive verbske·dad·dled, ske·dad·dling, ske·dad·dles Informal
Origin of skedaddleProbably alteration of British dialectal scaddle, to run off in fear, from scaddle, wild, thievish, skittish, from Middle English scathel, wild, harmful, probably of Old Norse origin; akin to skadha, to hurt, scathe.
(third-person singular simple present skedaddles, present participle skedaddling, simple past and past participle skedaddled)
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 skaÃ°i (“harm"). Possibly related to the Greek ÏƒÎºÎÎ´Î±ÏƒÎ¹Ï‚ (skedasis, “scattering"), ÏƒÎºÎµÎ´Î±ÏƒÎ¼ÏŒÏ‚ (skedasmos, “dispersion"). (US) Possibly related to scud or scat.