/ ˈʃɜːlɒk; NAmE ˈʃɜːrlɑːk/ (also Sherlock Holmes / həʊmz; NAmE hoʊmz/) noun
( informal , sometimes ironic ) a person who tries to find an explanation for a crime or sth mysterious or who shows that they understand sth quickly, especially sth that is not obvious :
Oh, well done, Sherlock. Did you figure that out all by yourself?
ORIGIN: From Sherlock Holmes, a very clever detective in stories by Arthur Conan Doyle, published in the late 19th and early 20th centuries.