Speculate/ˈspekjuleɪt/ Definition 1 of 3Pro Tip 1/3Hypothetical Thought Use 'speculate' when imagining scenarios without proof or evidence. Fans love to speculate about the future of their favorite TV shows. Pro Tip 2/3Avoid as Fact Speculate does not confirm anything, it expresses uncertainty. He refused to speculate on the outcome of the negotiations. Pro Tip 3/3Curiosity Expression Use when expressing curiosity or pondering about mysterious topics. We often speculate about the secrets of the universe.