1
general::
Phrase(s): on the lam
running from the police. (Underworld.) • Richard has been on the lam for a week now. • The gang leader broke out of prison and is still on the lam.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
Running away, especially from the police, as in He's always in some kind of trouble and perpetually on the lam. The origin of this slangy term of the 1800s is not known.
American Heritage Idioms