This is another completely moronic claim made in Daniel Cassidy’s obscenely ridiculous trashfest, How The Irish Invented Slang. Cassidy claims that the word scram comes from the Irish scaraim, meaning ‘I get away, I escape, I depart, I separate.’
According to the dictionary, the verb scar means part, separate, divide or spread. Here are some examples of how the word is used in Irish:
Scaradh na gcompánach. The parting of companions, ‘the parting of the ways’.
Tá siad scartha anois. They are separated now.
Ní maith leis scaradh lena chuid airgid. He doesn’t like parting with his money.
Is deacair scaradh leis an ulpóg sin. It’s hard to get rid of that flu.
Rinne siad aoileach a scaradh ar an pháirc. They spread manure on the field.
It really wouldn’t be used the way Cassidy is claiming, as the equivalent of split in modern American slang, to mean run away or leave. If it were, why would anyone say scaraim, which means I separate. Why I? How can one person separate or spread on their own? Why not you, or yous, or let’s? The answer is, of course, because if you don’t say scaraim it doesn’t sound anything like scram!
Back in the real world, scram is almost certainly a contraction of scramble, which dates back to at least the 16th century in English and refers to ‘moving or climbing hurriedly, especially on the hands and knees’ or ‘an unceremonious scuffle or struggle.’