scooby
/ˈskuːbi/(also scoobie) informal (chiefly Scottish )
noun
not to have a scooby: = not to have a clue.
Origin
1990s; earliest use found in The Glasgow Herald. Short for ScoobyDoo, the name of a cartoon dog which features in several U.S. television series and films (which typically include the name of the dog in the title), as rhyming slang for clue.