enigma

"Troilus and Cressida" has always been regarded as a sort of enigma.

As for Jane Temple's view of this business, that remained an enigma.

Whether he will buy his fleet abroad or build it himself is at present an enigma.

By the dignity of my profession, it must be so:—Now there's a solution to the enigma.

The Queen then condescended to explain the whole of the enigma to me.

For he seems, as it were, to have composed an enigma for the purpose of making an experiment.

I told you the truth when I said that the cipher letter was an enigma to me.

Watching a coast as it slips by the ship is like thinking about an enigma.

The enigma is only made clear by sacrifice, and the gift of heaven is in the hands of every man.

That was the enigma, one which would have been exciting, if the solution had not been so prompt and so tame.