Marvellous stories, flattery. Ex. He deals in the wonderful, he is full of blarney. Grose derives this word from the Blarney stone, a triangular stone on the very top of an ancient castle of that name in the county of Cork, in Ireland, extremely difficult of access; so that to have ascended it, was a proof of perseverance, courage, and agility, whereof many are supposed to claim the honor who never achieved the adventure. Hence, in England, they say, "He has licked the Blarney stone," i. e. he deals in the wonderful.--Dictionary of the Vulgar Tongue.
Dr. Jamieson doubts the Irish origin of this word, and adopts the French etymon baliverne, a lie, a fib, gull; also, a babbling, idle discourse.--Cotgrave, Dictionary.