I don't have a clue. ✬

Tom doesn't have a clue. ✬

Tom certainly doesn't have any clue about how things work around here. ✬

We have no clue where he is. ✬

I haven't got a clue. ✬

You really don't have a clue, do you? ✬

I have no clue what you're talking about. ✬

I don't have the slightest clue. ✬

You don't have a clue. ✬

I have absolutely no clue. ✬