The term 'Shakespearean Sobriquet' refers to a nickname or title given to William Shakespeare, the famous English playwright and POET. The crossword solution for this term is 'BARD, ' which is a four-letter word. The term 'BARD' is derived from the Old Celtic word 'bardos, ' which means 'POET.' It is often used to refer to someone who is a master of poetry, music, and storytelling, which is an apt description of William Shakespeare.