not have a clue

Idioms  

1. 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.

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Example Sentences

You might not have a clue it exists - let alone that you might need to train it.

From BBC

Asked about that finding, Welby said: "You can believe it or not, I did not have a clue."

From BBC

I really do not have a clue how this one will go, so I suppose the sensible thing for me to go for is a draw,

From BBC

It'd be silly to go through life and not have a clue about that guy, 'cause he's just one of those people.

From Salon

“Eric Hovde does not have a clue what he’s talking about,” she said on MSNBC.

From Seattle Times