Theorize
Part of speech: verb
Definition: to formulate theories, especially about some specific subject to speculate
Conjecture
Part of speech: noun
Definition: A statement or an idea which is unproven, but is thought to be true; a guess.A supposition based upon incomplete evidence; a hypothesis.A statement likely to be true based on available evidence, but which has not been formally proven.The interpretation of signs and omens.
Part of speech: verb
Definition: To guess; to venture an unproven idea.
Example sentence: Pretty much every night of their lives, my 8-year-old sons have absorbed themselves entirely in books. As toddlers, they pointed out pictures, made conjectures; lately, we find them in their bunk beds embarked upon two-hour comic-reading benders.