Not give or not worth a continental
The original expression was that something or other was not worth a Continental Dollar. The expression was first coined during the American War of Independence, referring to the paper money or promissory notes issued by the Continental Congress, the ruling body comprising the 13 American colonial states that rebelled and broke away from Britain in 1775. By the end of the war, this paper money was virtually worthless thus giving rise to the original expression, not worth a Continental Dollar. Shortly thereafter, by dropping the ‘dollar’ part, it became figurative for anything worthless and by the late 19th century made its way across the Atlantic to Britain. These days, it is often expressed as not giving a continental, which means not caring about or not giving credence to something or other.