What does SCOT-FREE mean?

The Kentucky Fried Movie - Scot Free

Scot-Free - Idioms - ESL British English Pronunciation

SCOT FREE -From "The Kentucky Fried Movie" - 1977

Scot-free Meaning

DPP Allowed MARIO’s KILLERS To WALK SCOT-FREE + ELDOR VENDOR Woman KILLED Other In COCKY DISPUTE

Where did the saying scot free originate?