- (countable & uncountable) Speculation is the ideas you have about the truth when you don't have all the important information.
- There has been a lot of talk and speculation about what will happen in the final game.
- Any answer to that question would be pure speculation.
- (uncountable) Speculation is the process of thinking about the truth when you don't have all the important information.
- After a great deal of speculation, I decided that he must have done it.
- (uncountable) Speculation is risky investing with the hope of making a large profit.