1. conjecture
It's conjecture. There's been a lot of conjecture about the marriage.
It´s not based on evidences It's conjecture.
How or why they died is a matter of conjecture
Amy wa sure that Jane had stolen her diamond bracelet, but her conjecture turned out to be erroneous
Well, you can only conjecture how it happened.
In any case, you are wrong in your conjecture.
We can conjecture that it may be advantageous for a particular bird to be known to its neighbors or its mate.