have a clue

not have a clue

To know absolutely nothing (in general, or about something specific). My brother thinks he can maintain his social life after he has kids. He doesn't have a clue! You don't have a clue how that thing works, do you?
See also: clue, have, not

have a clue (about something)

Fig. to know anything about something; to have even a hint about someone or something. (Usually negative.) I don't have a clue about where to start looking for Jim. Why do you think I have a clue about Tom's disappearance?
See also: clue, have
References in classic literature ?
As long as this man has no idea that anyone can have a clue there is some chance of securing him; but if he had the slightest suspicion, he would change his name, and vanish in an instant among the four million inhabitants of this great city.
Del Monte Foods, who conducted the survey, said most Americans admit they are not getting the daily recommendation of fruits and vegetables and "don't have a clue when it comes to understanding the new Dietary Guidelines for Americans".
"I did not have a clue what I wanted to do as a career, so I joined Three A's Pertemps Training.