If someone is on the lam or if they go on the lam, they are trying to escape or hide from someone such as the police or an enemy. [mainly US, informal]
He was on the lam for seven years. [+ for]
Idioms:
on the lam [mainly US]
trying to escape or hide from someone, for example the police or an enemy
He was arrested on Friday, after living on the lam since 1999.