conceivable

He has lied to me, the villain, in every conceivable way.

“When I said ‘appears’ I meant that it was conceivable that he had himself taken off the ring.”

Under no conceivable circumstances were the plans to be taken from the office.

“Presuming that it is an appointment,” continued the Inspector, “it is of course a conceivable theory that this William Kirwan—though he had the reputation of being an honest man, may have been in league with the thief.