They put at a safe distance those unmentionable, unrecognized things that otherwise are allowed to enter our minds only as nightmares.

How could I preserve those memories (and for that matter, all the other priceless 1960's-era films of me doing unmentionable things with water balloons)?

As is common in most modern discussions the unmentionable thing is the pivot of the whole discussion.

She had torn her clothes here, and wept, and done all manner of unmentionable things.

He may have known unmentionable things about all his friends.

That woman have the impertinence to send you to ask for unmentionable things on Sunday?

Against another wall was a large basin, probably holding something unnatural to which unmentionable things had been done.

Other than those unmentionable things, I feel wonderful.

She does unmentionable things but discreetly, out of camera range.