1. formed an opinion or theory without firm evidence; guessed based on incomplete information
Usage: past tense of conjecture

Examples

• Scientists conjectured that the planet had water based on early observations.
• She conjectured that he was late because of traffic.
• Historians have long conjectured about the true identity of the anonymous author.
• Without more data, researchers could only have conjectured about the cause.
• The detective conjectured that the suspect had inside knowledge.
• Ancient philosophers conjectured about the nature of the universe.
• He conjectured that the company’s profits would decline this quarter.