It was believed that 'Scot' was a Scottish term used in 13th century for money paid to buy food or drink at a tavern. Anyone who left without paying was said to “go scot-free”. The idiom “get off scot-free” or “go scot-free” means to escape punishment or get acquitted from a crime. The person essentially gets away without paying the price for his misdeed. In case of avoiding any monetary payment, it implies a deliberate move to evade paying one’s dues. So going scot-free could mean escaping without getting penalized or remain away from incurring the due payments.
The term “Scot-Free” has nothing to do with the Scottish as it is popularly believed. The word “Sceot” means “a tax” in Old English and as a matter of fact, 'Scot and lot' referred to a type of medieval municipal tax which residents had to pay. In this context, a person who would evade paying the tax is said to have got off scot free. Another version suggests that the word 'scot' is related to a slate used in pubs to mark the bills. A person who did not pay the pub bill on his scot was said to “get off scot-free”.
The term scot-free has evolved from its original meaning in Old English to describe the act of escaping from any kind of fiscal punishment or otherwise. For instance, children often fake stomach aches to be away from school and remain scot-free. Naughty boys with remorse in their eyes escape scot- free in spite of their pranks. It is often used in the context of suspects who are not convicted by saying that the person is fortunate to “go scot-free’.
It is a common misconception to associate the idiom “to get off scot-free” with the Scottish people as they were reputed to be frugal with their money. But the fact is that the term “scot” has its origins in the vocabulary of Old Norse to mean “payment” made to a sheriff or landlord. So a person who gets away without paying is termed as “getting off scot-free". The term then came to be used in UK to describe a kind of taxation for the poor relief which was levied in the 13th century. People do not approve paying taxes and anyone who escaped paying the taxes was called as going “scot-free”.