William Safire wrote in the New York Times in 1998 that on the lam means “running away” or “being a fugitive from the law…” “The origin of the expression is in heated dispute among slang etymologists.” Allan Pinkerton, the first “private eye” said that pickpockets would say “lam” when they secured a wallet from a victim.” There is a Scandinavian verb lam that as early as 1525 was used to describe a wife “lamming him,” meaning to beat, pound, or strike” her husband. Mark Twain used the term twice to mean “to beat” in both instances. The connection is that “…to avoid a feared lamming (related to slamming), one lams. “