A judgment, estimate, or opinion arrived at by guessing
To draw an inference on the basis of inconclusive evidence or insufficient information
Life is constant probing and testing, conjecture and refutation.
I have never counted the number of posts, but I conjecture that there are less than five.
We have to conjecture what the Board's reasons were.
If a conjecture is realized it is very difficult to see how it remains a conjecture.
As this business was to be entered into without the usual capital, it may not be easy to conjecture where those means, that will still be indispensable to every such undertaking, were to be obtained.