Lam is a sudden or hurried departure often associated with being in conflict with the law: “Finding the police escort lax, two culprits managed to lam while being taken to the court and are still at large.”
Lamb , on the other hand, has the following meanings:-
1. A young sheep typically less than one year old: “I am a meat eater but I prefer lamb to chicken.”
2. A favorite or vulnerable individual: “Christ can be called a perfect lamb because he went on the cross for the sake of common people.”