To be uninformed or ignorant about something; be ''clueless'': ''You know who I was?'' ''Haven't got a clue''(WWII British armed forces)
Idioms and Phrases with not have a clue
not have a clue
Have no idea or inkling about something, as in Jane doesn't have a clue as to why John won't call her, or Do you know what's wrong with the boiler?—No, I haven't a clue. This usage was first recorded in 1928.