Conjecture n. 1. inference or judgement based on inconclusive evidence 2. a conclusion based on a guesswork the detectives made various conjectures about the motive of the murder. [middle english, from lation conicere (to throw together), com- (with) + jacere (to throw)] which part of the dictionary entry will a student understand similar words? a. the part of speech b. the definitions of conjecture c. the sample sentence d. the definition of the root word conicere